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Advanced Digital Signal Analyzer Probes
Low-Frequency Signals with Ease and
Precision
Significant new features include absolute internal
calibration in the user's choice of engineering units, digital
band selectable or 'zoom' analysis, fully annotated
dual-trace CRT display with X and Y axis cursors, digital
storage of data and measurement setups on a tape
cartridge, and a random noise source to provide test
stimulus.
by Richard H. Grote and H. Webber McKinney
DIGITAL SIGNAL ANALYSIS has become a
widely used technique for the analysis of me-
chanical structures, noise, vibration, control systems,
electronic networks, and many other devices and
physical phenomena.
In the past, digital signal processing equipment has
been expensive, difficult to move, and has required
an operator that understands digital signal analysis as
well as the problem to be solved. While there is a def-
inite need for such sophisticated laboratory equip-
ment, there is also a need for instrumentation that is
less expensive, easier to use, and more portable.
Such an instrument is the new Model 5420A Digi-
tal Signal Analyzer (Fig. 1). The 5420A is a two-chan-
nel instrument that analyzes signals in the
dc-to-25-kHz frequency range. The new analyzer has
a two-tone dynamic range of 75 dB and amplitude
flatness of 0.1 dB. Band selectable (zoom) analysis
provides 0.004-Hz frequency resolution anywhere in
the measurement band. The 5420A makes many
powerful time domain and frequency domain mea-
surements, including transient capture and time
averaging, auto and cross correlation, histogram, lin-
ear spectrum, auto and cross spectrum, transfer func-
tion, coherence function, and impulse response. All
measurements are continuously calibrated, and can
be easily recalibrated in the operator's engineering
units. Built-in random noise stimulus and a digital
tape cartridge for storing data records and instrument
set-ups make the 5420A a complete measuring sys-
tem. Measurement results are displayed on a fully an-
notated, dual-trace, high-resolution CRT, and can be
output directly to an optional X-Y recorder or digital
plotter. The display provides three graphic formats
and 14 choices of coordinates. The display scale can
Cover: In a dramatic dem-
onstration of its versatility,
HP engineers used a Model
5420A Digital Signal Ana-
lyzer to determine the re-
sponse and vibrational char-
acteristics of a compound
bow of the type used by
tournament archers. Ac-
celerometers mounted on the bow provided the
input signals to the analyzer. (Bow provided by
Jennings Compound Bow, Inc.)
In this Issue:
Advanced Digital Signal Analyzer
Probes Low-Frequency Signals with
Ease and Precision, by Richard H.
Grote and H. Webber McKinney .... page 2
Front End Design for Digital Signal
Analysis, by Jean-Pierre Patkay, Frank
R.F. Chu, and Hans A.M. Wiggers . . page 9
Display and Storage Systems for a
Digital Signal Analyzer, by Walter M.
Edgerley, Jr. and David C. Snyder . . page 14
Digital Signal Analyzer Applications,
by Terry L. Donahue and Joseph P.
Oliverio page 17
Printing Financial Calculator Sets New
Standards for Accuracy and Capability,
Roy E. Martin
page 22
Printed in U.S. A
©Hewlett-Packard Company, 1977
Fig. 1. Model 5420 A Digital Sig-
nal Analyzer is a dual-channel in-
strument that analyzes signals in
the dc-to-25-kHz frequency
range. It makes many powerful
time and frequency domain mea-
surements, including spectrum,
transfer function, and impulse re-
sponse. Results are displayed on
a fully annotated dual-trace CRT in
any of three graphic formats and
14 choices of coordinates.
be set either by the operator or automatically to maxi-
mize the use of the display surface.
Measurements
The new digital signal analyzer makes an extensive
set of time domain and frequency domain measure-
ments. Here is a description of each measurement and
an example of where the measurement is useful.
Time Record Average. This measurement is used to
average time records, or to capture transient time
records. The Fourier transform (linear spectrum) of
the time waveform is also provided. Time averaging
is used primarily for improving the signal-to-noise
ratio of time functions. A synchronous time signal is
required to trigger the time average.
Autocorrelation. The primary application for the
autocorrelation function is also pulling signals out of
noise. However, the autocorrelation function does
not require time synchronization. The disadvantage
of autocorrelation is that the autocorrelation func-
tion of complex signals is difficult to interpret. As a
result, this technique is mainly used for sinusoids,
which are preserved under autocorrelation.
Crosscorrelation. The crosscorrelation function is
mathematically similar to the autocorrelation func-
tion. However, crosscorrelation is used to determine
the relationship between two signals. A major appli-
cation of crosscorrelation is the determination of rela-
tive delays between two signals.
Histogram. The histogram provides an estimate of the
probability density function of the incoming time
waveform. The histogram can provide the operator
with an indication of the statistical properties of a
signal.
Linear Spectrum. The linear spectrum is the fre-
quency domain equivalent of the time record average.
The result of this measurement is a display of rms
amplitude versus frequency. The linear spectrum re-
quires time synchronization for averaging, and con-
tains both magnitude and phase information.
Power or Auto Spectrum. This is the measurement
performed by a traditional spectrum analyzer, that is,
power as a function of frequency. The auto spectrum
is calibrated in units of mean square for sinusoidal
signals, power spectral density for random signals, or
energy density for transient signals. The auto spec-
trum is used for characterizing signals in the fre-
quency domain.
Cross Spectrum. The cross spectrum is the frequency
domain equivalent of the crosscorrelation function.
The cross spectrum produces a display of relative
power versus frequency. The cross spectrum can be
used to determine mutual power and phase angle as a
function of frequency.
Transfer Function. The transfer function measure-
ment characterizes a linear system in terms of gain
and phase versus frequency. When the operator se-
lects this measurement, the following measurements
are also provided.
Coherence (y 2 ). This function is related to the signal-
to-noise ratio (S/N =7 2 /(l-y 2 )). It indicates the de-
gree of causality between the output and the input
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Fig. 2. Band selectable analysis (BSA) makes it possible to
zoom in on a narrow frequency band and examine the detailed
structure ot measured data with resolution as fine as 0.004 Hz.
Here the baseband measurement (a) shows a resonance at
about 5 kHz. The 0.4-Hz resolution of the BSA measurement
(b) reveals that there are actually two resonances there.
as a function of frequency. A coherence of 1 indicates
perfect causality.
Input and Output Auto Spectrum. See above.
Impulse Response. The time domain equivalent of
the transfer function. The impulse response shows
the time response of the system to an impulsive input.
Band Selectable Analysis (BSA)
Band selectable (zoom) analysis concentrates
the full resolution of the analyzer in a narrow fre-
quency band of the user's choice. This narrow band
can be placed any where in the 25-kHz bandwidth. Its
width is selectable and may be less than 1 Hz. BSA can
provide better than 4-mHz resolution, and measure-
ments below 250 Hz can be made with a resolution
better than 40 /juHz. This resolution is obtained using
purely digital techniques with no sacrifice in accu-
racy or dynamic range. An example of the power of
BSA is shown in Fig. 2. The 25-Hz resolution of the
baseband measurement of Fig. 2a indicates the pres-
ence of a single resonance centered at 5 kHz. The
0.4-Hz-resolution BSA measurement of Fig. 2b clear-
ly shows two resonances in the vicinity of 5 kHz.
Advanced Triggering Capability
The 5420A offers the operator a wide choice of trig-
gering capabilities, including free run, internal trig-
gering on either channel, external triggering ac or dc
coupled, and remote start.
When the analyzer is free running, it acquires and
processes input data as fast as it can. For measure-
ment bandwidths below the instrument's real-time
bandwidth, this results in overlapped processing of
input data. In this case, processing periods over-
lap input data records, and the analyzer processes
the latest available data. Overlapped processing in-
creases the variance reduction per unit time.
All triggering modes allow the operator to condi-
tion triggering by entering a per-channel pre-trigger
or post-trigger delay. Pre-trigger delays up to the time
record length and post-trigger delays up to 40 sec-
onds can be accommodated. Post-trigger delays are
necessary when there are inherent delays in the mea-
surement process, such as in measuring the transfer
characteristics of an auditorium. Pre-trigger delay is
of particular importance when triggering on impul-
sive signals that have all their energy focused in a
very short time interval; without pre-trigger delay it is
very difficult to capture the leading edge of the sig-
nal's energy.
Easy to Use
An important design objective for the 5420A Digi-
tal Signal Analyzer was that it be easy to use, both for
the novice and for the experienced operator. Front-
panel design for such a powerful, flexible instrument
poses particular problems. These were solved in part
by using the CRT display to extend and simplify the
front panel (Fig. 3). The display presents measure-
ment parameters and status information. Instead of
having to inspect all of the front-panel controls to de-
termine how the instrument is set up, the operator
simply pushes the VIEW key and the setup is dis-
played on the CRT. The CRT is also used to display
menus of choices from which the user makes selec-
tions of measurements, averaging, input signals, and
triggering.
Display Features
Once a measurement has been specified, it is in-
itiated by pushing the START button. As soon as the
first time record has been digitized and processed,
fully calibrated measurement results appear on the
display. If stable averaging was chosen, the measure-
Fig. 3. CRT display extends the
front panel, helping to make the
new analyzer easy to use for both
the novice and the experienced
operator. For example, pushing
the view key causes the instru-
ment's status to be displayed.
Other keys display lists of choices
from which the user can select
measurement parameters.
ment continues until the specified number of aver-
ages has been done. If one of the other averaging types
— exponential, peak channel hold, or peak level
hold — was selected, the instrument continues pro-
cessing data and displaying calibrated results indef-
initely until the operator manually stops the measure-
ment by pushing the PAUSE/CONT button. Pushing this
button a second time resumes the measurement by
averaging new data into the previous result.
Measurement results can be viewed in any of sever-
al display formats. Fig. 2a shows the most basic FULL
format. The instrument automatically scales and cali-
brates the X and Y axes, generates an internal grati-
cule, and labels both axes. The type of measurement
result — transfer function in this case — is indicated
in the upper left corner of the display and the num-
ber of averages used to make the measurement is
indicated in the upper right corner. In the lower left
corner is an "echo field" that tells the user the last se-
quence of front-panel buttons pushed, and in the
lower right corner are error messages, such as ADC
overflow.
Two measurement results can be viewed simultan-
eously, either UPPER/LOWER (Fig. 1), or one super-
imposed on the other, FRONT/BACK (Fig. 2b). The re-
sults are fully annotated and calibrated, and either
trace can be modified independently of the other.
These formats are of considerable benefit for such
purposes as viewing two parameters of a measure-
ment simultaneously (e.g., magnitude and phase of a
transfer function), or comparing a result with that of a
previous measurement.
Results can be displayed in the following coor-
dinate systems: magnitude of the function, phase,
log magnitude, log of the horizontal axis (when log
magnitude versus log frequency is selected, the result
is the classical Bode plot), real part of the function,
imaginary part, real part plotted versus imaginary
(Nyquist plot), and log magnitude versus phase
(Nichols plot, useful in control theory applications).
In dual display modes, the coordinates of the two
traces can be chosen independently.
Cursor Capability
A major user convenience of the 5420A is its
powerful cursor capability. The instrument can dis-
play two independent cursors in each axis. The posi-
tions of the cursors are indicated at the top of the dis-
play. At the intersection of the X cursor and the
waveform is an intensified point, and the value of that
point on the waveform is indicated on the display
along with the cursor position. Hence one application
of the cursor is to indentify numerical values associ-
ated with a measurement. For example, an X axis cur-
sor can be used to identify the amplitude at a particu-
lar frequency, or the two Y axis cursors can be used to
identify what frequency components are, say, 50 dB
below a peak level.
Although the cursors are primarily means of identi-
fying specific values of a measurement result, they
can be used in other ways to enhance the power and
the convenience of the instrument. In conjunction
with the control and setup keys, the cursors can be
used to define the center frequency and bandwidth of
a new measurement.
In conjunction with the display operator keys, the
cursors have other uses. If an X cursor is moved to co-
incide with a resonance of a transfer function, the fre-
quency and the percent critical damping of that res-
onance can be determined by pushing the PEAK key.
The Module I/O Bus (MIOB)
The module input/output bus (MIOB) is the interconnect
scheme for all of the modules of the 5420A Digital Signal Ana-
lyzer (cartridge, display, filters, ADC, etc.). It consists of 1 6 bidi-
rectional data lines, one handshake pair for sending commands
from computer to module, and one handshake pair for every-
thing else (status flow from module to computer and data trans-
fers). The computer can use the bus at any time to send com-
mands to a module. The modules must accept commands at any
time. However, they may send status or send or receive data
only when they "own" the bus.
To maintain high speed at the system level and controllable
response time, it is necessary to reduce the hardware and soft-
ware overhead required for bus access. On the hardware side,
this is accomplished by using burst mode transfers from
64-word FIFO memories. On the software side, all I/O is per-
formed using two special microcoded opcodes, xcw and Xio.
The computer does not use the conventional direct memory ac-
cess (DMA) hardware. DMA would be useful only during the
burst portion of the data transfer. It has no facilities to control re-
sponse time between bursts or to perform the buffer blocking
and I/O chaining required. The microcode facility of the 21 MX
K-Series Computer provides far greater performance.
A time log of activity on the bus during normal system opera-
tion might look like this:
■ Display sends a code word (CW) then inputs 64 words
■ ADC sends CW then outputs 32 words
■ Display sends CW then inputs 64 words
■ Display sends CW then inputs 26 words
■ Computer sends S60HZSYNC (interrupt on power line sync)
to display
■ Keyboard sends CW
■ ADC sends CW then outputs 32 words
Transactions are either commands from the computer to a
module or burst mode transfers initiated by a module and al-
ways beginning with a code word containing the device's
name and status. This structure causes the computer to be in-
terrupt-driven, that is, most bus transactions are initiated by a
device. Normally, real-time software associated with so many
devices is very complex, but again, the ability of microcode to
provide just the right elementary operations keeps complexity to
a minimum.
Each module (display, ADC, etc.) is controlled by a separate
software module called a device control process (DCP). Each
DCP appears to own the entire computer all of the time and is
unaware of interrupts. Hence the DCPs can be programmed
using simple in-line structures instead of complex, shared-com-
puter, save/restore registers— interactive structures charac-
teristic of most interrupt-driven systems. The mechanisms for
this simplification are the two MIOB I/O opcodes: XCW and XIO.
When an MIOB interrupt (XCW) occurs, a microcoded inter-
rupt processor automatically saves registers, reads the code
word (CW) on the bus, and branches through a table to the
appropriate DCP. When it is ready to relinquish control, that
DCP performs another XCW opcode, causing the interrupt
branch table to be updated, registers restored, and the high-
level processing resumed. This entire procedure costs the DCP
only 20>s per XCW, or 20>s per interrupt.
The other special I/O opcode, XIO, is a pseudo-DMA with
many embellishments. An inescapable issue whenever hard-
ware and software meet is the mapping of data structures. The
hardware designer provides a 128-word sector, an 80-word
FIFO memory, or a 2K-word refresh buffer, while the software
designer needs an N-byte text buffer, a 1000-word data buffer,
or something else. The XIO opcode directly addresses this
problem. The XIO opcode's operand is a chain of four-
word control blocks that define the desired I/O transfer
— for example, "output three commands, then input 50 words,
then output two commands." The control blocks tell where to
get the commands or data by pointing to the buffer structure,
which may include fixed buffers, variable buffers (e.g., the
next 50 words in a 1000-word buffer), buffers requiring block-
ing or unblocking (a composite buffer having many physical
pieces, some perhaps deactivated), circular buffers, double
buffers, or some other type. This opcode transforms what is
usually implemented in dynamic real-time consuming soft-
ware into static definitions of data structure. For example, the
display DCP that produces the calibrated data display pro-
vides the display hardware with 64-word data bursts followed
by two-word command bursts. It extracts these from seven
buffers containing ASCII code, cursors, graticules, annotation,
and so on. Each sub-buffer is separate, variable in length, and
in its own natural format. Yet the DCP is only 15 lines of code
instead of the many hundreds of lines of time-critical code
normally required. Furthermore, the average data transfer
bandwidth is higher than could have been obtained with DMA.
It exceeds 200 kHz at system level, including amortization of
all overhead (code words, invisible interrupts, other devices,
interrupt latency, etc.) Conventional approaches would
probably yield system level average transfer bandwidth much
less than 1 kHz because of this overhead, plus that associated
with sharing DMA between I/O channels and sharing I/O
channels between devices, and because of the software re-
quired to convert buffer formats into DMA's linear se-
quential forms. There is also the general program complexity
that seems to be always associated with interrupt subroutines.
A time-sequenced record of all MIOB transactions is auto-
matically maintained by the extended I/O instructions. This
trace-file capability is very useful in tracking down any l/O-relat-
ed problems. Another feature, backgrounding, allows DCPs to
create other software processes that run at the same time as the
DCP. This allows a DCP to do time-consuming operations (e.g.,
scan a large buffer) without tying up the MIOB at all.
-David C. Snyder
Critical damping is a measure of the sharpness of
the resonance and is equal to 1/2Q, where Q is the qual-
ity factor familiar to electrical engineers. Finally,
the cursor can be used to identify the harmonics of a
particular spectral component. Pushing the HARMON-
IC button causes the harmonics of the frequency
component, identified by an X cursor, to be intensi-
fied on the CRT.
Display Operators
Powerful post-processing capabilities allow the
user to manipulate measurement results. It is possible
to add, subtract, multiply, or divide a measurement
by another measurement or by a complex constant.
These operators could be used, for example, to calcu-
late the percent difference between two measure-
ments. Using another post-processing operation, the
5441 OA Analog-to- Digital Converter 54470B Digital Filter
2105K-Series Processor
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1
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1
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48K RAM
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3K ROM
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Rear
Cartridge
Cartridge Intertace
Character
Generator
Vector
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5443A Processor
Analog
Plotter CRT
External
Fig. 4. Block diagram of Model
5420 'A Digital Signal Analyzer. The
three principal sections — central
processor, analog input section,
and display — are connected by a
common bus. The input section
consists of a dual-channel
analog-to-digital converter and
digital filter. An HP 21 MX K-Series
Computer serves as the central
processor.
user can multiply or divide a frequency domain result
by jo), which has the effect of differentiating or inte-
grating that measurement in the time domain. These
operations are useful for converting accelera-
tion spectrums to displacement spectrums, charge to
current, and so forth. The POWER key allows the oper-
ator to calculate the total power in the display, the
power at a specific line or in a band defined by the
cursors, or the power in the harmonics of a particular
frequency when the harmonic cursor mode is en-
abled. The POWER key turns the instrument into a
frequency selective power meter.
Analyzer Organization
A block diagram of the 5420A Digital Signal
Analyzer is shown in Fig. 4. The three principal ele-
ments are the central processor, the analog input sec-
tion, and the display/cartridge interface section.
These three functional sections are connected by a
bus known as the module input/output bus (MIOB), a
50-conductor ribbon cable on the backplane of the
5420A (see box, page 6). The MIOB conveys all con-
trol and data between the processor and the input sec-
tion and between the processor and the display sec-
tion by means of a 1 6- wire parallel bus and eight con-
trol signals. By having all system I/O pass through one
port of the processor, and by using only one cable,
module interconnections were greatly simplified
while maintaining high data transfer rates.
The processor is the central controller and data
manipulator of the 5420A. The processor is a micro-
programmed HP 21MX K-Series Computer with 48K
words of MOS random-access memory (RAM) and 3K
words of read-only memory (ROM). The ROM is used
for microprogram storage. An arithmetic booster
board significantly increases the computational
power of the instrument. This 90-IC board bolts onto
the bottom of the computer's CPU board. The MIOB
interface connects the processor to the other sections
of the instrument, while an HP-IB option interfaces
the 5420A to the Hewlett-Packard interface bus (IEEE
Standard 488-1975).
The input section consists of a dual-channel ana-
log-to-digital converter (ADC) and digital filter.
Each input channel has a floating differential input
(to eliminate ground loops present in many measure-
ment environments), anti-aliasing filters to remove
unwanted spectral components above one-fourth the
sampling rate, and a 12-bit successive approximation
analog-to-digital converter. The input channel also
has an analog trigger capable of triggering on an ex-
ternal signal or either of the analog inputs, and a noise
generator for producing stimulus signals. The noise
bandwidth is automatically adjusted to be as close as
possible to the bandwidth of the measurement being
made. The digital filter, which is the key to the great
frequency resolution capability of the instrument,
translates the frequency components of the sampled
data and then digitally filters the result with one of 16
filter bandwidths.
The third section is the display and cartridge unit.
The instrument has two cartridges, both interfaced
through the same drive electronics. The front-panel
cartridge is used for measurement results and setup
state storage. Up to 120 measurement results and 50
setup states can be stored on this cartridge. The inter-
nal cartridge is used to "boot-up" the instrument at
initial power turn-on. This boot-up operation is
necessary because the RAM memory in the processor
is volatile, so its contents need to be loaded when
power is first applied.
The display is the high-resolution HP 1332 A CRT
with full vector and character generation circuits. An
external CRT and an analog plotter can be driven di-
rectly from the connections on the rear of the display
section.
singing in his church choir
Richard H. Grote
■ Dick Grote has been in the digital
|§ signal analysis lab since he joined
I" HP in 1969. Now a section man-
ager, he was project leader for the
5420A hardware. Born in In-
dianapolis, Indiana, he received
his BSEE degree in 1969 from the
University of Kansas and hisMSEE
in 1971 from Stanford University.
He's married to an HP mathemati-
cian (and author of a 1974 article in
these pages), and lives in Palo
Alto, California. His interests in-
clude woodworking and home
projects, reading, old movies,
and a number of sports.
getting into
H. Webber McKinney
Webb McKinney received his
BSEE and MSEE degrees in 1968
and 1969 from the University of
Southern California. He Joined HP
in 1 969 as a sales engineer, and a
year later moved into the digital
signal analysis lab, where he's
now a section manager. He was
project leader for the 5420A
software and human interface.
Webb was born in Upland, in
southern California, and now lives
in Los Altos. He spends his spare
time working on his house, playing
tennis, bicycling, playing folk
yoga. He's married and has two
Frequency and Time Characteristics
FREQUENCY DOMAIN:
MODES:
PASS8AND: Bandwidth (BW) about center frequency (CF).
CENTER FREQUENCY (CF): 0.016 Hz to 25 kHz, nominal.
CF SETTABILITY: Within 1.6 Hz ot desired value, typically 0.016 Hz
below 250 Hz.
BANDWIDTHS (BW): 1 6 selections trom 0.8 Hz to 25 kHz for CF of 25 kHz
and below Additional 16 selections from 0.008 Hz to 250 Hz for CF of
250 Hz and below.
RANGE: if s CF ± BW/2^25 kHz.
BASEBAND: At to bandwidth (BW).
CF: Specifying CF selects baseband mode.
BW: Same as for passband mode.
RANGE: Same as bandwidth
RESOLUTION (At): Automatically computed from bandwidth selection.
RANGE: 16 *iHz to 100 Hz
TIME DOMAIN:
TIME RECORD LENGTHS (T): 32 selections trom 0.005 seconds to 32 000
seconds nominal.
RESOLUTION (At): Automatically computed Irom T.
RANGE: 10 (iseconds to 64 seconds.
Measurement Characteristics
MEASUREMENTS PERFORMED:
TIME DOMAIN: View Input (Channel 1 and Channel 2): Time Average: Auto-
correlation: Crosscorrelation; Impulse Response (Impulse Response is
available as part ol the transfer function measurement)
FREQUENCY DOMAIN: Linear Spectrum; Auto Power Spectrum; Cross
Power Spectrum, Power Spectral Density, or Energy Density: High Resolution
Auto Spectrum; Transfer Function; Coherence.
HISTOGRAM (Probability Density Function).
Note: Passband mode does not operate for time record, linear spectrum, or
AVERAGING TYPES: All averaging lypes provide continuously calibrated re-
sults and may be paused, resumed, er cleared by the operator at any point in
STABLE: Equal weighting, stops after reaching selected number ot averages.
EXPONENTIAL: Stable up to number ol averages selected, then exponential
with decay constant egual to number of averages selected.
PEAK CHANNEL HOLD: Holds maximum value in each channel (Aulo Spec-
trum only).
PEAK LEVEL HOLD: Holds spectrum corresponding to maximum value of
cumulative chennels (Auto Spectrum only).
NUMBER OF AVERAGES: From 1 to 30 000 ensemble averages
SIGNAL TYPES:
SINUSOIDAL: Optimizes peak amplitude accuracy.
RANDOM: Normalizes power to 1 Hz noise bandwidth
TRANSIENT: Normalizes energy lo 1 Hz noise bandwidth lor iransient analysis.
IMPACT: Same as transient but allows preview ot inpul signals before analysis.
SPECIFICATIONS
HP Model 5420 A Digital Signal Analyzer
CALIBRATION: All measurements are fully calibrated, including provision for a
user entered calibration factor (K=C1/C2) for each channel (K1.K2) to give
results in engineering units.
Measurement
Sinusoidal
Signal Type
Random
Transient
Auto Spectrum
(K-Vrms) 2
(K-V)*sec
Cross Spectrum
K1 K2 Vrms*
K1-K2-Vrms*
H2
K1-K2 V*sec
Transfer Function
KZ/K1
Coherence
Unitless
Linear Spectrum
KVrms
Time Record
K-V
Auto Correlation
(K-V)=
Cross Correlation
K1K2-V 2
Histogram
-KRangeto +K Range
Input Characteristics
INPUT CHANNELS: Two— via 8NC o
INPUT IMPEDANCE:
FRONT-PANEL INPUT: 1 Mil shunted by <50 pF.
REAR-PANEL INPUT; 1 Mil shunted by <200 pF.
INPUT COUPLING:
SINGLE ENDED: dc or ac on each channel separately. Ac down 3 dB at 3 Hz
nominal.
FLOATING: Differential input, dc only.
COMMON MODE REJECTION RATIO: »65 dB below 120 Hz for .differential
floating input.
MAXIMUM COMMON MODE VOLTAGE: ±10 volts.
FULL-SCALE RANGES; ±0.1,0.25,0.5, 1, 2.5,5, and 10 volts peak
AMPLITUDE FLATNESS: ±0.1 dB over the entire frequency range (±0.05 dB
typical).
CHANNEL-TO-CHANNEL MATCH:
AMPLITUDE: ±0.1 dB ( = 0.05 dB typical).
PHASE: ±5 degrees (±2 degrees typical).
TRIGGER MODES: Free run with overlap processing; internal on either input
signal; external, ac or dc ( +5V max level).
SLOPE: + or -
LEVEL: Adjustable from 10% to 90% ol full scale.
DELAV: Independent delays on each channel, either pre- or post-trigger.
PRE- TRIGGER: sT
POST-TRIGGER: «4000T
HESOLUTION: ±At
DYNAMIC RANGE: 5*75 dB for each full-scale range setting. Measured by taking
at least 16 averages of a minimum detectable signal in the presence of a full-
scale, in-band signal with random signal type selected and a frequency separa-
tion between signals ot at least 6% of the selected bandwidth. Includes distor-
tion, noise, and spurious signals caused by full-scale, outside energy within
Noise Output Characteristics
TYPE: Broadband random, unfiltered.
BANDWIDTH:
BASEBAND MODE: dc to selected bandwidth.
PASSBAND MODE: dc to center frequency plus one-half the bandwidth,
MAXIMUM OUTPUT CURRENT: ±50 mA peak.
OUTPUT LEVEL: Adjustable from 0.35 Vrms to 3.5 Vrms typically. Also
3.5 Vrms "cal" position.
CREST FACTOR: 2.5:1 typical
Display Characteristics
NUMBER OF TRACES: One or two— designated A and B
DISPLAY FOHMATS: Full (single trace): Upper/lower (dual trace); Front/Back
(dual trace).
ACTIVE TRACE: The active trace may be designated A, B, or A and B.
DISPLAY CURSORS: Cursors are displayed in full format as either a line or a band
on the X axis, the Y axis, or both axes simultaneously Cursors may be swept via
their control keys or set to values explicitly entered by the operator.
DISPLAY UPDATE: Display is buffered and refreshed at the line frequency rate.
Miscellaneous Characteristics
SELF-TEST: A self-test function is provided.
HP-IB: An optional HP-IB interface is available. A rear-panel switch selects talk
only or addressable operating modes. HP-IB is Hewlett-Packard's implementa-
tion of IEEE Standard 488-1 975 "Digital Interface for Programmable Instrumenta-
it may be initiated by contact closure to ground vi
REMOTE START: Measur
rear-panel BNC connect
EXTERNAL SAMPLING: A rear-panel connector is provided for an external
sampling signal at TTL levels. The frequency provided must be four times the
desired range (100 kHz single, 75 kHz dual channel maximum). Internal filters
may be switched out if desired.
EXTERNAL CRT OUTPUT: Horizontal, vertical and intensity outputs are provided
to drive an external large screen display Horizontal and vertical outputs provide
a nominal range ol ± Vb volt Intensity output provides - 14 volt to ( 1 volt. Display
must have a 5 MHz bandwidth.
ANALOG PLOTTER OUTPUT: A rear-panel ribbon connector provides horizontal.
vertical, pen-lift and servo on/off outputs lo an analog plotter.
General Characteristics
DIMENSIONS:64.14cm(25.25in)D*42.55cm(16.75in)W- 40.64 cm (16.0 in) H.
WEIGHT; 52.16 kg (115 lbs), net.
POWER: 110V -20%, optional 230V +20%, 800 VA max. (600 watts max.).
48-66 Hz.
PRICE IN U.S.A.: $29,900
MANUFACTURING DIVISION: SANTA CLARA DIVISION
5301 Stevens Creek Boulevard
Santa Clara. California 95050 U.S.A.
Details of the operation of these sections are de-
scribed in the articles that follow.
Acknowledgments
Pete Roth originally conceived the idea for the pro-
duct. Bob Puette provided support. Bob Reynolds, Al
Low, and Gary Schultheis did the product design. Al
Langguth designed the digitizer. Norm Rogers de-
signed the arithmetic booster board, did micropro-
gramming, and provided general signal processing
expertise. Ralph Smith, Dave Conklin, Tom Robins,
Mary Foster, and Chuck Herschkowitz developed the
software. John Curlett helped with the digital filter
and the front panel. Dennis Kwan and Walt Noble
provided support in production. Thanks also to Bob
Perdriau and Ken Ramsey for their marketing efforts,
to Hal Netten, John Buck, and Richard Buchanan for
manuals and service policy, and to Ken Jochim and
Skip Ross for many suggestions and management tal-
ent. S
Front-End Design for Digital Signal
Analysis
by Jean-Pierre D. Patkay, Frank R.F. Chu, and Hans A.M. Wiggers
THE INPUT CHANNELS of the new 5420A
Digital Signal Analyzer perform the dual func-
tion of data acquisition and preprocessing. Prepro-
cessing minimizes data storage and computational
demands on the central processor while providing
the user with increased measurement capability.
Some signal analyzers using the Fourier transform
are limited to baseband measurements, that is, the
measurement band extends from dc to a maximum
frequency. If increased resolution is desired, more
samples must be taken, requiring more data storage
and processing time. In the 5420A front end is a hard-
ware implementation of band-selectable analysis
(BSA), a measurement technique that makes it pos-
sible to perform spectral analysis over a frequency
band whose upper and lower limits are independent-
ly selectable. 1 Increased resolution can be obtained
by narrowing the measurement bandwidth, without
increasing the data block size. BSA is realized by digi-
tally filtering the sampled input signal to remove all
data corresponding to frequencies outside the desired
band.
A functional diagram of the 5420A front end is in-
cluded in Fig. 4 on page 7. The hardware is divided
into two plug-in modules that share a common power
supply. Two analog input channels are contained in
the 54410A Analog-to-Digital Converter Module. All
digital filtering operations are contained in the
54470B Digital Filter Module. In combination, the
two modules provide a dynamic range of 75 dB
over seven input ranges from 100 mV full-scale
to 10V full-scale.
A noise generator in the ADC module provides a
stimulus signal for transfer function measurement.
The noise generator, a combination of an analog noise
source and a digital filter, generates a flat energy
spectrum from dc to the maximum frequency of the
measurement. The noise bandwidth tracks the select-
ed measurement bandwidth.
The analog trigger input in the ADC module has
a pseudo-logarithmic potentiometer to provide max-
imum trigger-level sensitivity around zero volts.
Software features allow the user to advance or
delay the measurement time window with respect to
the trigger; this can be done independently for each
channel.*
Analog Inputs
Each analog input channel has a buffered input, an
anti-aliasing filter, and a 12-bit successive approx-
imation analog-to-digital-converter (ADC). The
maximum measurement frequency is determined by
the sampling frequency, which is the conversion rate
of the ADC, and by the anti-aliasing filter. According
to the Nyquist sampling theorem, the maximum mea-
surement frequency cannot exceed half the sampling
frequency or measurement errors will occur. The
anti-aliasing filters insure that there are no
higher-frequency components that can fold down or
alias into the measurement band as a result of the
sampling process. Since they do not have an infinite-
ly sharp cutoff, they further limit the maximum mea-
surement frequency. In the 5420A the maximum sam-
ple rate is 102.4 kHz and the maximum measurement
frequency is specified as 25.6 kHz.
Without BSA the input channel would be sam-
pled at the lowest possible frequency that would still
include the measurement band of interest. This gives
maximum resolution for a fixed data block size, but
requires a large number of available sample rates and
*To use this feature, both channels must be running constantly. The software determines
when to take data. The trigger signal merely tells the software that the trigger condition has been
satisfied.
R, L,
+ VSAr-
(a)
RC1
L,
-* — 1(— i—\\V-^A\ — »
1/R,
L, 1/R,
D,
RC2
(b)
V V
V,
Fig. 1 . The analog anti-aliasing filters in the 5420 A use the
FDNR (frequency dependent negative resistance) active filter
approach. Any general passive LCR network can be trans-
formed into network of resistors, capacitors, and FDNR ele-
ments that has the same voltage transfer function. Here circuit
(a) has been transformed into circuit (b). D 1 is the FDNR
element. Resistors RC1 and RC2 have been added to (b) to
define the dc behavior.
either a large number of fixed filters or tracking fil-
ters, both of which are costly.
The digital filter allows us to avoid this expense.
The ADC runs at only two sample rates, 102.4 kHz
and 1.024 kHz, so only two anti-aliasing filter ranges
are required. Higher measurement resolution in inter-
mediate bands is obtained by means of the digital
filter.
Anti-Aliasing Filters — the FDNR Approach
The two anti-aliasing filter ranges in each input
channel are 30 kHz and 300 Hz. In this low frequency
range, the only feasible low-pass filter type is an
active filter.
The active anti-aliasing filters in the 5420A use
the FDNR (frequency dependent negative resistance)
approach developed by Dr. L. Bruton. 2 Basically, any
general passive LCR network can be transformed into
a topologically similar network that contains resis-
tors, capacitors, and FDNR elements. The new net-
work has the same voltage transfer function as the
original LCR network. To illustrate, consider the
passive LCR network shown in Fig. la. Let V out /V in
= N(s)/D(s).
Now let us make an impedance transformation,
multiplying each component by 1/s. The transformed
network is as shown in Fig. lb. For this circuit,
Vi,
N(s]/s N(s]
D(s)/s = D(s]
Dj = 1/CjS 2 is the FDNR element. Resistors RCl and
RC2 are added to define the dc behavior.
The FDNR element Dj can be realized by the circuit
shown in Fig. 2. Z in is a frequency dependent nega-
tive resistance.
For the 30-kHz FDNR filter used in the 5420A, the
design objectives dictated a seventh-order ellip-
tical filter with passband ripple of 0.01 dB and re-
jection band attenuation of 90 dB. The correspond-
ing normalized low-pass filter is illustrated in
Fig. 3. 3
Now, for f c = 30 kHz and C = 2000 pF, R = llwC
= 2.65 kfl. Multiplying each normalized component
value by 2650 results in the FDNR filter shown in
Fig. 4. This circuit has greater than 80 dB of stop-band
attenuation for frequencies above 60 kHz. The pass-
band characteristics of any two filters are matched
within ±0.1 dB and phase shifts are matched within
±2° throughout the entire 5420A operating tempera-
ture range of 0°C to 50°C. The circuit components
consist of high-bandwidth operational amplifiers,
1% mica dipped capacitors, and 1% metal film
resistors.
Digital Filter
The digital filter can operate in two modes,
a baseband mode and a passband mode. In the
baseband case the band to be analyzed is be-
tween dc and some maximum frequency f 1 =£25.6 kHz,
**=3"*M
c, z,
R, z 2
:c, 2,
R 2 Z 4
R 3 z.
Fig. 2. A realization of a frequency dependent negative resis-
tance.
10
0.9785
1.7744
1.71476
0.89708
0.03789 V 0.17237 i- 0.1266
_ 1 .39201 ZjZ 1 .38793 ZjZ 1 .2737
V V V
Fig.. 3. Normalized low-pass filter having the characteristics
required for the 5420A's anti-aliasing filters.
as shown in Fig. 5a. The filter is switched into
the baseband mode and set to the narrowest band-
width that includes f v The available bandwidths
are given by
BW = 2" k
f„
2 =S k =£ 17
I = 104.2 kHz or 1.042 kHz
This gives a total of 32 bandwidth choices.
In a more general case the user wants to analyze a
band between two arbitrary frequencies fj and f 2 , as
shown in Fig. 5b. In this case the analyzer first
calculates a center frequency f = 1 /2(f 2 -f 1 ),
and by using the digital equivalent of a coquad mixer,
shifts the entire frequency spectrum to the left by
an amount f . This centers the desired analysis band
at dc. Second, a low-pass filtering operation is used to
obtain the desired bandwidth. However, there is a sig-
nificant difference here from the baseband measure-
ment. In Fig. 5a, only the positive frequency domain
is shown. This is appropriate because the digital sig-
nal stream coming from the ADC represents a real sig-
nal and therefore has the property that positive and
negative components are the same. 4 In the bandpass
measurement, the positive and negative frequency
bands are not the same, since the negative part con-
tains the information from fj to f and the positive
part contains the information from f to f 2 . As a con-
sequence, the samples describing the shifted spec-
trum are complex numbers instead of real ones.
This can also be seen mathematically. The effect of
shifting by f in the frequency domain is the same as
convolving the signal with the spectral component
e -jo) n -phis corresponds to multiplication of the
time-domain ADC signal x(nAt) by e~ io,ut = cosaj At -
jsinw At, and so the shifted signal is x(nAt) (cosw nAt
— jsin w nAt). Thus for every sample x(nAt) that goes
into the frequency shifter, two components come out,
a real part x(nAt)cosw nAt and an imaginary part
-jx(nAt)sin« nAt. The low-pass filter operation then
has to be performed on these complex points. For-
tunately, digital filtering operations are distributive,
that is, filtering a complex signal is the same as fil-
tering the real and imaginary parts separately. The
frequency shift and filter operation is shown schema-
tically in Fig. 6.
Frequency Shifter
To generate the values of sinw nAt and cosw nAt
for the frequency shift operation, 1024 samples of a
half-sine wave are stored in a read-only memory. The
ROM address register is incremented at the sample
frequency rate by an amount corresponding to w .
This register contains 16 bits. The two most signifi-
cant bits are decoded to determine which quadrant of
85.6k 2.6k
4.55k
2.35k
r>r
<hA\\^
4.22k
x2 Amplifier
Fig. 4. The active FDNR filter derived from the normalized filter of Fig. 3.
11
Fig. 5. Digital band selector in the 5420A Digital Signal
Analyzer operates in either baseband mode or passband
mode. The user has a choice of 32 bandwidths (BW). Sam-
pling frequency f s is either 104.2 or 1.042 kHz.
the sine wave the sample is in. For the first quadrant
the sample stored in ROM is output. For the second
quadrant the ROM address is inverted to get the cor-
rect value. For the third quadrant the value stored in
ROM is used, but the output is inverted (this is done
in the multiplier). For the fourth quadrant both the
ROM address and the output value are inverted. To
obtain the cosine samples a similar process is used.
The ADC sample and the cosw t sample are multi-
plied in a hardware 12-bitx 12-bit multiplier. The ac-
tual multiply takes 1.2 microseconds. A new sample
can be handled every 2.4 /as, corresponding to a maxi-
mum sample rate of about 400 kHz for one channel.
Since the 5420A has two channels, the maximum
sample rate is 200 kHz. The actual sample rate is
102,400 samples per second, and the output of the
multiplier consists of 409,600 samples per second.
The digital filter has to be fast enough to handle this
x(nAt)
-Hg>-
Digital Low-Pass
Filter
Real
Part
cos (&) nAt)
-j sin (&> nAt)
>®-
Digital Low-Pass
Filter
Imaginary
Part
Fig. 6. Band selectable analysis is implemented by a fre-
quency shift and digital filtering operation.
Fig. 7. A simple first-order digital filter can be implemented
with one adder, one shift register, and one multiplier.
many samples without losing any.
Digital Filter
The digital filter is based on a linear difference sys-
tem. Input samples coming from the ADC or the fre-
quency shifter are temporarily stored in holding reg-
isters. The input samples are then combined with pre-
vious sample values to give an output value. In the
simplest case (Fig. 7) the output would be y(nt) =
x(nT)+ax((n-l)T), which could be implemented
with one adder, one shift register, and one multiplier.
Analysis of the circuit of Fig. 7 is most easily done
in the frequency domain using the Fourier transform.
If the Fourier transform of x(nT) is X (jco) then it can
be shown that the Fourier transform of the delayed
time series x((n-l)T) is e~ iwT X(ja)). Thus
Y(jw) = Xf>] + ae HwT X(ja>).
The transfer function of the circuit of Fig. 7 is
Hew
YG«)
1 + ae
-jojT
X(jo>)
or, using Euler's expression for e~ iwT ,
H [)(o) = 1 + acoswT — jasinwT.
Similar equations can be worked out for second-
order difference equations. In particular, it is possible
to take the delayed samples and add them to the input
x(nT) _i
K 1
*i JjJMi
K 2 ^^^^^^ L 2
l V(nT)
Fig. 8. A second-order digital filter section.
12
as well as to the output (see Fig. 8). The difference
equations are
y (nT) = x(nT) + K iyo ((n-l)T) + K 2 y (n-2)T)
y(nT) = L y (nT) + Ljr ((n-1)T) + L 2 y ((n-2)T)
The transfer function is
Y(jw) L + L e- iwT + L e- 2iwT
H(jo>]
X(jco)
1 - K 1 e- ja,T - K,e- 2iwT
or
H(jo
L + L^oswT + L 2 cos2wT - jL,sinaiT - jL 2 sin 2cuT
1 - K^ostuT - K 2 cos2a)T + jK,sinwT + jK,sin2cuT
The magnitude of this transfer function is
L u + L,cosa/T + L 2 cos2(oT) 2 + (L,sincuT-L 2 sin2wT) 2
|H(»| 2 =
at dc [u>
;i - K,cos<oT - K 2 cos2<uT) 2 + (K,siiWT + K 2 sin2wT) 2
= 0),
H(jo>)
L() + J-"l + '-'2
1 - K t - K 2
The coefficients L , L lt L 2 , K 1 and K 2 may be selected
to give unity gain at dc as well as the desired pass-
band and rejection band characteristics.
For the 5420A, to obtain the required 80-dB out-of-
band rejection, it was necessary to implement two of
the sections shown in Fig. 8, each having different
coefficients. The final overall filter characteristic is
shown in Fig. 9.
Resampling
It should be noted that the filter characteristic is
dependent on the sample frequency f s . If f s were
twice as low, the filter passband would be twice as
narrow. Also, the frequency content of the filtered
signal is roughly half the content of the pre-filter sig-
nal. According to the Nyquist sampling theorem,
the filter output can be resampled at half the original
rate without losing information. The new sample
frequency is i' s = V2f s .
If this resampled signal is sent through the same
filter the bandwidth is halved again. By successively
filtering and resampling, the bandwidth can be re-
duced by powers of two. The same filter handware
can be used for these consecutive steps if the filter is
designed so that calculation of the first "filter pass"
Hans A.M. Wiggers
Hans Wiggers received his en-
gineering degree from the Techni-
cal University at Delft, The Nether-
lands, in 1965. He joined HP in
1972 with several years' experi-
ence in digital IC design. He de-
signed the 54470 Digital Filter
module for the 5420A. Born in
Amsterdam, Hans is married, has
two sons, and lives in Los Gatos,
California. He's a soccer coach,
an amateur photographer, and a
recorder player.
Fig. 9. Each 5420A digital filter consists of two second-order
sections and has the characteristic shown here.
Jean-Pierre D. Patkay
Pierre Patkay received BS and MS
degrees in engineering from Har-
vey Mudd College in 1973. He
Joined HP's digital signal analysis
lab the same year. Pierre served
as project leader and production
engineer for the 54410 ADC Mod-
ule for the 5420A. Born in
Pasadena, California, he's mar-
ried, lives in Los Altos, California,
and occupies his spare time with
tennis, alpine skiing, ski touring,
yoga, and "pulling weeds."
Frank Rui-Feng Chu
Frank Chu designed the front end
of the 54410 ADC Module and the
ADC FIFO memory board for the
5420A. He's been doing circuit
design for HP spectrum analyzers
and digital signal analyzers since
he joined the company in 1970.
Frank received his BSEE degree
from the University of Washington
in 1970 and his MSEE degree from
Stanford University in 1972. He's
married, has a daughter, and lives
in Santa Clara, California. He plays
table tennis, collects stamps and
coins, and is working on an MBA
degree.
13
takes less than half the sample time. The other half of
the available time may then be used for calculation of
one of the other "passes". An algorithm to do this is
built into the 5420A. The partial sums are stored in
the memory instead of a shift register, and the con-
trol section regulates which pass is being calculated.
Because the digital filter must be able to handle
409,600 samples per second, and half of the time must
be devoted to other passes, the maximum allowable
time for one calculation is about 1.25 /jls. Actually
the filter performs the calculations in about half this
time. E
References
1. H.W. McKinney, "Band-Selectable Fourier Analysis,"
Hewlett-Packard Journal, April 1975.
2. L.T. Bruton, "Network Transfer Functions Using the Con-
cept of Frequency - Dependent Negative Resistance," IEEE
Transactions on Circuit Theory, Vol. CT-16, pp. 406-408,
August 1969.
3. A.I. Zverev, "Handbook of Filter Synthesis," pp. 278-280.
4. R.N. Bracewell, "The Fourier Transform and Its Appli-
cations," McGraw-Hill, 1965.
Display and Storage Systems for a Digital
Signal Analyzer
by Walter M. Edgerley, Jr. and David C. Snyder
WHILE DATA IS BEING TAKEN into the 5420A
Digital Signal Analyzer and is being manipu-
lated by the processor, the analyzer must be display-
ing this data graphically and alphanumerically,
without flicker, and in a clear, clean manner.
A key factor in realizing the required performance
is the high-resolution HP-designed CRT. It has a
viewing area of 9.6 cm x 11.9 cm and produces a
keenly focused spot of 0.33 mm diameter everywhere
in the viewing area, more than adequate to display
alphanumeric characters 1.6 mm x 2.6 mm in size.
Data is transmitted via the MIOB (see box, page 6),
which services all modules in the 5420A. The display
receives data in 16-bit x 64-word bursts from the pro-
cessing module. The high-speed bus makes it pos-
sible to maintain a flicker-free directed-beam display
without large amounts of memory.
Fig. 1 shows the signal flow from the processor
to the CRT. The data passes from the processor to the
display control board via the interface and timing
board. This board not only handshakes the data from
the processor, but generates all timing signals for
digital operations.
On the control board, the data is tested for data
type, which is either graphic or alphanumeric. If
graphic, it is assumed to be in horizontal and verti-
cal pairs and is sent to the stroke generator. If al-
phanumeric, it is first sent to the character genera-
tor for processing into the proper horizontal and
vertical bit patterns for character construction and
then to the stroke generator. The stroke generator
transforms the digital information into the appro-
priate horizontal, vertical, and blanking analog
signals.
Character Generator
Fig. 2 is a block diagram of the character generator.
It is an algorithmic state machine (ASM) that accepts
seven-bit ASCII codes and generates appropriate hor-
izontal and vertical bit patterns to construct the dis-
play alphanumerics. The bit pattern construction is
dependent on two control lines (A and B) at the out-
put of the ROM. There are four possible control
situations:
■ Load new ASCII code into ROM address register
(RAR), but do not increment character counter
Interface
and
Timing
^|
Control
,
'
w
^|
f
From
Processor
Stroke
Generator
^
1
l
r -
1
r
y
r
Horizontal 1
Amplifier 1
Vertical
Amplifier
Blanking
Amplifier
High-Voltage
Supply
Fig. 1. 5420 'A display system receives data from the central
processor via the MIOB and displays it on a high-resolution
directed-beam CRT.
14
HEWLETT-PACKARD JOURNAL
Volumes 25, 26, 27, 28
September 1973 through August 1977
Hewlett-Packard Company, 1501 Page Mill Road, Palo Alto, California 94304 U.S.A.
Hewlett-Packard Central Mailing Department, Van Heuven Goedhartlaan 121,
Amstelveen-1134 The Netherlands
Yokogawa-Hewlett-Packard Ltd., Shibuya-Ku, Tokyo 151 Japan
PART 1 : Chronological Index
September 1973
A Low-Frequency Spectrum Analyzer that Makes Slow Sweeps
Practical, William L. Hale and Gerald E. Weibel
A High-Performance Beam Tube for Cesium Beam Frequency
Standards, Ronald C. Hyatt, Louis F. Mueller and Terry N.
Osterdock
October 1973
The Logic Analyzer: A New Kind of Instrument for Observing
Logic Signals, Robin Adler, Mark Baker, and Howard D.
Marshall
A Pulse Generator for Today's Digital Circuits, Reinhard Falke
and Horst Link
November 1973
A Self -Contained, Hand-Held Digital Multimeter — A New Con-
cept in Instrument Utility, Robert L. Dudley and Virgil L. Laing
A Portable High-Resolution Counter for Low-Frequency Mea-
surements, Kenneth /. MacLeod
A High-Speed Pattern Generator and an Error Detector for Testing
Digital Systems, Thomas Crawford, James Robertson, /ohn Stin-
son, and Ivan Young
December 1973
A Go-Anywhere Strip-Chart Recorder That Has Laboratory Accu-
racy, Howard L. Merrill and Rick A. Warp
Telecommunication Cable Fault Location from the Test Desk,
Thomas R. Graham and James M. Hood
High-Efficiency Modular Power Supplies Using Switching Regu-
lators, B. William Dudley and Robert D. Peck
January 1974
The Logic State Analyzer — Displaying Complex Digital Processes
in Understandable Form, William A. Farnbach
A Laser Interferometer that Measures Straightness of Travel,
Richard R. Baldwin, Barbara E. Grote, and David A. Harland
February 1974
Practical Oscilloscopes at Workaday Prices, Hans-Gunter
Hohmann
Laboratory Notebook — Sharp Cut-Off Filters for That Awkward
UHF Band
A Data Error Analyzer for Tracking Down Problems in Data Com-
munications, Jeffrey R. Duerr
March 1974
An Automatic, Precision 1-MHz Digital LCR Meter, Kohichi
Maeda
A Moderately Priced 20-MHz Pulse Generator with 16-Volt Out-
put, Gunter Krauss and Rainer Eggert
Laboratory Notebook — Logarithmic Amplifier Accepts 100 dB
Signal Range
Versatile VHF Signal Generator Stresses Low Cost and Portability,
Robert R. Hay
April 1974
Mass Memory System Broadens Calculator Applications, Havyn
E. Bradley and Chris J. Christopher
An Easily Calibrated, Versatile Platinum Resistance Thermometer,
Tony E. Foster
Speeding the Complex Calculations Required for Assessing Left
Ventricular Function of the Heart, Peter Dikeman and Chi-ning
Liu
May 1974
The "Personal Computer": A Fully Programmable Pocket Cal-
culator, Chung C. Tung
Programming the Personal Computer, R. Kent Stockwell
Designing a Tiny Magnetic Card Reader, Robert B. Taggart
Testing the-HP-65 Logic Board, Kenneth W. Peterson
Economical Precision Step Attenuators for RF and Microwaves,
George R. Kirkpatrick and David R. Veteran
June 1974
A New Generation in Frequency and Time Measurements, James
L. Sorden
The 5345A Processor: An Example of State Machine Design,
Ronald E. Felsenstein
Time Interval Averaging: Theory, Problems, and Solutions, David
C. Chu
Part 1 : Chronological Index (continued)
Third Input Channel Increases Counter Versatility, Arthur S. Muto
A Completely Automatic 4-GHz Heterodyne Frequency Converter,
Ali Bologlu
Interface Bus Expands Instrument Utility, Bryce E. Jeppsen and
Steven E. Schultz
July 1974
Powerful Data Base Management System for Small Computers,
flichard E. Mclntire
Quality Frequency Counters Designed for Minimum Cost, Lewis
W. Masters and Warren /. O'Buch
A Versatile Bipolar Power Supply/ Amplifier for Lab and Systems
Use, Santo Pecchio
An Automatic Exposure Control for a Lab-Bench X-Ray Camera,
/ohn L. Brewster
August 1974
Measuring Analog Parameters of Voiceband Data Channels, Noel
E. Damon
Transient Measurements, Paul G. Winningho/f
The 4940A Sine Wave Transmitter, Richard T. Lee
Nonlinear Distortion Measurements, Donald A. Dresch
Envelope Delay Distortion Measurements, Richard G. Fowles and
Johann J. Heinzl
Peak-to-Average Ratio Measurements, Erhard Ketelsen
Microwave Integrated Circuits Solve a Transmission Problem in
Educational TV, James A. Hall, Douglas J. Mellor, Richard D.
Pering, and Arthur Fong
September 1974
A 250-MHz Pulse Generator with Transition Times Variable to
Less than 1 ns, Gert Globas, Joel Zellmer, and Eldon Cornish
Optimizing the Design of a High-Performance Oscilloscope, P.
Kent Hardage, S. Raymond Kushnir, and Thomas /. Zamborelli
A Thin-Film/Semiconductor Thermocouple for Microwave Power
Measurements, Weldon H. Jackson
Microelectronics Enhances Thermocouple Power Measurements,
John Lamy
October 1974
A User-Oriented Family of Minicomputers, John M. Stedman
Microprogrammable Central Processor Adapts Easily to Special
User Needs, Philip Gordon and Jacob R. Jacobs
Testing the 21MX Processor, Cleaborn C. Riggins and Richard L.
Hammons
All Semiconductor Memory Selected for New Minicomputer
Series, Robert J. Frankenberg
The Million-Word Minicomputer Main Memory, John S. EI ward
A Computer Power System for Severe Operating Conditions,
Richard C. Van Brunt
November 1974
Distributed Computer Systems, Shane Dickey
A Quality Course in Digital Electronics, James A. Marrocco and
Barry Bronson
Simplified Data-Transmission Channel Measurements, David H.
Guest
December 1974
Improved Accuracy and Convenience in Oscilloscope Timing and
Voltage Measurements, Walter A. Fischer and William B. Risley
Laboratory Notebook — An Active Loop-Holding Device
A Supersystem for BASIC Timesharing, Nealon Mack and
Leonard E. Shar
Deriving and Reporting Chromatograph Data with a
Microprocessor-Controlled Integrator, Andrew Ste/anski
Adapting a Calculator Microprocessor to Instrumentation, Hal
Barraclough
January 1975
The Hewlett-Packard Interface Bus: Current Perspectives, Donald
C. Loughry
Putting Together Instrumentation Systems at Minimum Cost,
David W. Ricci and Peter S. Stone
Filling in the Gaps — Modular Accessories for Instrument Sys-
tems, Steven E. Schultz and Charles R. Trimble
A Quiet, HP-IB-Compatible Printer that Listens to Both ASCII and
BCD, Hans-Jurg Nadig
A Multifunction Scanner for Calculator-Based Data Acquisition
Systems, David L. Wolpert
Minimal Cost Measuring Instruments for Systems Use, Gary D.
Sasaki and Lawrence P. Johnson
Visualizing Interface Bus Activity, Harold E. Dietrich
February 1975
High-Sensitivity X-Y Recorder Has Few Input Restrictions,
Donald W. Huff, Daniel E. Johnson, and John M. Wade
Digital High-Capacitance Measurements to One Farad, Kunihisa
Osada and Jun-ichi Suehiro
Computer Performance Improvement by Measurement and Mi-
croprogramming, David C. Snyder
March 1975
A High-Performance 2-to-18-GHz Sweeper, Paul R. Hernday and
Carl J. Enlow
Broadband Swept Network Measurements, John J. Dupre and
Cyril J. Yansouni
The Dual Function Generator: A Source of a Wide Variety of Test
Signals, Ronald J. Riedel and Dan D. Danielson
April 1975
A Portable 1100-MHz Frequency Counter, Hans J. Jekat
Big Timer/Counter Capability in a Portable Package, Kenneth J.
MacLeod
A High-Current Power Supply for Systems that Use 5-Volt IC
Logic Extensively, Mauro DiFrancesco
Band-Selectable Fourier Analysis, H. Webber McKinney
May 1975
An Understandable Test Set for Making Basic Measurements on
Telephone Lines, Michael B. Aken and David K. Deaver
A Computer System for Analog Measurements on Voiceband Data
Channels, Stephen G. Cline, Robert H. Perdriau, and Roger F.
Rauskolb
A Precision Spectrum Analyzer for the 10-Hz-to-13-MHz Range,
Jerry W. Daniels and Robert L. Atchley
June 1975
Cost-Effective, Reliable CRT Terminal Is First of a Family, James
A. Doub
A Functionally Modular Logic System for a CRT Terminal, Arthur
B. Lane
A High-Resolution Raster Scan Display, Jean-Claude Roy
Firmware for a Microprocessor-Controlled CRT Terminal, Thomas
F. Waitman
A Microprocessor-Scanned Keyboard, Otakar Blazek
Packaging for Function, Manufacturability, and Service, Robert B.
Pierce
July 1975
Modularity Means Maximum Effectiveness in Medium-Cost Uni-
versal Counter, James F. Horner and Bruce S. Corya
Using a Modular Universal Counter, Alfred Langguth and William
D. Jackson
Synthesized Signal Generator Operation to 2.6 GHz with Wide-
band Phase Modulation, James A. Hall and Young Dae Kim
Applications of a Phase-Modulated Signal Generator, James A.
Hall
August 1975
The Logic State Analyzer, a Viewing Port for the Data Domain,
Charles T. Small and Justin S. Morrill, Jr.
Unravelling Problems in the Design of Microprocessor-Based Sys-
tems, William E. Wagner
A Multichannel Word Generator for Testing Digital Components
and Systems, Arndt Pannach and Wolfgang Kappler
September 1975
ATLAS: A Unit-Under-Test Oriented Language for Automatic Test
Systems, William R. Finch and Robert B. Grady
Automatic 4.5-GHz Counter Provides 1-Hz Resolution, Ali
Bologlu
A New Instrument Enclosure with Greater Convenience, Better
Accessibility, and High Attenuation of RF Interference, Allen F.
Inhelder
Part 1: Chronological Index (continued)
October 1975
Digital Power Meter Offers Improved Accuracy, Hands-Off Opera-
tion, Systems Compatibility, Alien P. Edwards
Very-Low-Level Microwave Power Measurements, Ronald E. Pratt
Active Probes Improve Precision of Time Interval Measurements,
Robert W. Offermann, Steven E. Schultz, and Charles R. Trimble
Flow Control in High-Pressure Liquid Chromatography, Helge
Schrenker
November 1975
Three New Pocket Calculators: Smaller, Less Costly, More Power-
ful, Randall B. Neff and Lynn Tillman
Inside the New Pocket Calculators, Michael /. Cook, George
Fichter, and Richard Whicker
Packaging the New Pocket Calculators, Thomas A. Hender
A New Microwave Link Analyzer for Communications Systems
Carrying Up to 2700 Telephone Channels, Svend Christensen
and Ian Matthews
December 1975
A 100-MHz Analog Oscilloscope for Digital Measurements, Allan
I. Best
An Oscilloscope Vertical-Channel Amplifier that Combines
Monolithic, Thick-Film Hybrid, and Discrete Technologies, Joe
K. Millard
A Real-Time Operating System with Multi-Terminal and Batch/
Spool Capabilities, George A. Anzinger and Adele M. Gadol
Real-Time Executive System Manages Large Memories, Linda W.
Averett
January 1976
An Automatic Selective Level Measuring Set for Multichannel
Communications Systems, /. Reid Urquhart
Designing Precision into a Selective Level Measuring Set, Hugh P.
Walker
Designing a Quiet Frequency Synthesizer for a Selective Level
Measuring Set, John H. Coster
Making the Most of Microprocessor Control, David G. Dack
Real-Time Multi-User BASIC, James T. Schultz
February 1976
Laser Transducer Systems for High-Accuracy Machine Position-
ing, Andre F. Rude and Michael /. Ward
Electronics for the Laser Transducer, William E. Olson and Robert
B. Smith
Using a Programmable Calculator as a Data Communications
Terminal, James E. Carlson and Ronald L. Stickle
March 1976
A Cesium Beam Frequency Reference for Severe Environments,
Charles E. Heger, Ronald C. Hyatt, and Gary A. Seavey
Calibrated FM, Crystal Stability, and Counter Resolution for a
Low-Cost Signal Generator, Robert R. Collison and Ronald E.
Kmetovicz
A 50-Mbit/s Pattern Generator and Error Detector for Evaluating
Digital Communications System Performance, Ivan R. Young,
Robert Pearson, and Peter M. Scott
April 1976
Electronic Total Station Speeds Survey Operations, Michael L.
Bullock and Richard E. Warren
Designing Efficiency into a Digital Processor for an Analytical
Instrument, John S. Poole and Len Bilen
May 1976
New CRT Terminal Has Magnetic Tape Storage for Expanded
Capability, Robert G. Nordman, Richard L. Smith, and Louis A.
Witkin
Mini Data Cartridge: A Convincing Alternative for Low-Cost, Re-
movable Storage, Alan J. Richards
Laboratory Notebook — A Logarithmic Counter
June 1976
Third-Generation Programmable Calculator Has Computer-Like
Capabilities, Donald E. Morris, Chris J. Christopher, Geoffrey W.
Chance, and Dick B. Barney
High-Performance NMOS LSI Processor, William D. Eads and
David S. Maitland
Character Impact Printer Offers Maximum Printing Flexibility,
Robert B. Bump and Gary R. Paulson
Mid-Range Calculator Delivers More Power at Lower Cost,
Douglas M. Clifford, F. Timothy Hickenlooper, and A. Craig
Mortensen
July 1976
A Direct-Reading Network Analyzer for the 500-kHz-to-1.3-GHz
Frequency Range, Hugo Vifian
Processing Wide-Range Network Analyzer Signals for Analog and
Digital Display, William S. Lawson and David D. Sharrit
A Precision RF Source and Down-Converter for the Model 8505A
Network Analyzer, Rolf Dalichow and Daniel R. Harkins
August 1976
Series II General-Purpose Computer Systems: Designed for Im-
proved Throughput and Reliability, Leonard E. Shar
An All-Semiconductor Memory with Fault Detection, Correction,
and Logging, Elio A. Toschi and Tak Watanabe
HP 3000 Series II Performance Measurement, Clifford A. Jager
September 1976
An Easier-to-Use Variable-Persistence/ Storage Oscilloscope with
Brighter, Sharper Traces, Van Harrison
An Automatic Wide-Range Digital LCR Meter, Satoru Hashimoto
and Toshio Tamamura
October 1976
Continuous, Non-Invasive Measurements of Arterial Blood Oxy-
gen Levels, Edwin B. Merrick and Thomas J. Hayes
Laboratory Notebook — A Signal-Level Reference
An Accurate Low-Noise Discriminator
Card-Programmable Digital IC Tester Simplifies Incoming Inspec-
tion, Eric M. Ingman
November 1976
A Pair of Program-Compatible Personal Programmable Cal-
culators, Peter D. Dickinson and William E. Egbert
Portable Scientific Calculator Has Built-in Printer, Bernard E.
Musch and Robert B. Taggart
The New Accuracy: Making 2 3 = 8, Dennis W. Harms
High-Power Solid-State 5.9-12.4-GHz Sweepers, Louis J.
Kuhlman, Jr.
The GaAs FET in Microwave Instrumentation, Patrick H. Wang
December 1976
Current Tracer: A New Way to Find Low-Impedance Logic-Circuit
Faults, John F. Beckwith
New Logic Probe Troubleshoots Many Logic Families, Robert C.
Quenelle
A Multifunction, Multifamily Logic Pulser, Barry Bronson and
Anthony Y. Chan
Probe Family Packaging, David E. Gordon
Multifamily Logic Clip Shows All Pin States Simultaneously,
Duiward Priebe
Interfacing a Parallel-Mode Logic State Analyzer to Serial Data,
Justin S. Morrill, Jr.
January 1977
A Logic State Analyzer for Microprocessor Systems, Jeffrey H.
Smith
Firmware for a Microprocessor Analyzer, Thomas A. Saponas
A Versatile, Semiautomatic Fetal Monitor for Non-Technical
Users, Erich Courtin, Walter Ruchsay, Peter Salfeld, and Heinz
Sommer
February 1977
A Fast-Reading, High-Resolution Voltmeter that Calibrates Itself
Automatically, Albert Gookin
A High-Speed System Voltmeter for Time-Related Measurements,
John E. McDermid, James B. Vyduna, and Joseph M. Gorin
Contemporary Design Practice in General-Purpose Digital Mul-
timeters, Roy D. Barker, Virgil L. Laing, Joe E. Marriott, and H.
Mac Juneau
March 1977
A New Series of Small Computer Systems, Lee Johnson
Part 1: Chronological Index (continued)
HP 1000 Operating System is Enhanced Real-Time Executive,
David L. Snow and Kathleen F. Hahn
Development and Application of Microprograms in a Real-Time
Environment, Harris Dean Drake
E-Series Doubles 21MX Performance, Cleaborn C. Riggins
How the E-Series Performance Was Achieved, Scott /. Stallard
Microprogrammed Features of the 21MX E-Series, Thomas A.
Lane
OPNODE: Interactive Linear Circuit Design and Optimization,
William A. Rytand
Viewpoints — John Moll on HP's Integrated Circuit Technology
April 1977
Silicon-on-Sapphire Technology Produces High-Speed Single-
Chip Processor, Bert E. Forbes
CMOS/SOS, David Farrington
Miniature Oscilloscope Probes for Measurements in Crowded Cir-
cuits, Carolyn M. Finch, Marvin F. Estes, and Lawrence A.
Gammill
A Small, Solid-State Alphanumeric Display, John T. Uebbing,
Peter B. Ashkin, and Jack L. Hines
May 1977
Signature Analysis: A New Digital Field Service Method, Robert
A. Frohwerk
Easy-to-Use Signature Analyzer Accurately Troubleshoots Com-
plex Logic Circuits, Anthony Y. Chan
Signature Analysis — Concepts, Examples, and Guidelines, Hans
/. Nadig
Personal Calculator Algorithms I: Square Roots, William E. Egbert
June 1977
A Wide-Ranging Power Supply of Compact Dimensions, Paul W.
Bailey, John W. Hyde, and William T. Walker
Remote Programming of Power Supplies Through the HP Inter-
face Bus, Emery Salesky and Kent Luehman
Coaxial Components and Accessories for Broadband Operation to
26.5 GHz, George R. Kirkpatrick, Ronald E. Pratt, and Donald R.
Chambers
Personal Calculator Algorithms II: Trigonometric Functions,
William E. Egbert
July 1977
Small Computer System Supports Large-Scale Multi-User APL,
Kenneth A. Van Bree
APL Data: Virtual Workspaces and Shared Storage, Grant J.
Munsey
APLGOL: Structured Programming Facilities for APL, Ronald L.
Johnston
APL/ 3000 Summary
A Dynamic Incremental Compiler for an Interpretive Language,
Eric J. Van Dyke
A Controller for the Dynamic Compiler, Kenneth A. Van Bree
Extended Control Functions for Interactive Debugging, Kenneth
A. Van Bree
CRT Terminal Provides both APL and ASCII Operation, Warren W.
Leong
August 1977
New 50-Megabyte Disc Drive: High Performance and Reliability
from High-Technology Design, Herbert P. Stickel
An Individualized Pulse/Word Generator System for Sub-
nanosecond Testing, Christian Hentschel, Gunter Riebesell, Joel
Zellmer, and Volker Eberle
PART 2: Subject Index
Month/Year
Apr. 1974
Sept. 1973
May 1977
June 1977
June
Apr.
Nov.
July
Nov.
Feb.
Aug.
May
Oct.
Jan.
Aug.
Jan.
Nov.
July
Sept.
May
Aug.
1974
1977
1975
1974
Aug. 1974
May 1975
1974
1974
1975
1977
1973
1974
1975
1977
1975
1976
1973
May 1975
1975
1975
Apr. 1976
Subject
A
Accounting system, desk-top computer
Adaptive sweep in a spectrum analyzer
Algorithm, personal calculator, square
root
Algorithms, personal calculator,
trigonometric
Algorithmic state machine design
Alphanumeric displays, solid-state
AM-to-PM conversion, detection of
Amplifier/ power supply
Model
9880A
3580A
Amplitude distortion, telephone
measurements
Amplitude distortion, telephone
measurements
Amplitude/ delay distortion
Analyzer, data transmission errors
Analyzer, digital pattern recognition
Analyzer, digital signature
Analyzer, logic (serial)
Analyzer, logic state (parallel)
Analyzer, logic state
Analyzer, logic state
Analyzer, microwave link
Analyzer, network, 0.5-1300 MHz
Analyzer, spectrum, 5 Hz to 50 kHz,
portable
Analyzer, spectrum, 10 Hz to 13 MHz
5345A
HDSP-2000
3790A
6825A/
6A/7A
4940A
5453A
3770A
1645A
1620A
5004A
5000A
1601L
1600S
1611A
3 790 A
8505A*
Analyzer, transmission parameter
Analyzing microprocessor-based
systems
Angle measurements, surveying
3580A
3571A/
3044A/3045A*
5453A
1600S
3810A
Apr. 1974 Angio analyzer
July 1977 APL (a programming language)
July 1977 APLGOL
July 1975 Applications for phase-modulated
generator
July 1975 Armed measurements, counter/timer/
DVM
Sept. 1975 ATLAS (abbreviated test language for
avionics systems)
Sept. 1973 Atomic frequency standard (cesium),
high-performance
Mar. 1976 Atomic frequency reference (cesium)
May 1975 Attenuator, classical problem
May 1974 Attenuators, coaxial, step, dc-18 GHz
June 1977 Attenuators, coaxial, step, dc-26.5 GHz
Feb. 1977 Autocalibration in a digital voltmeter
July 1974 Automatic exposure control for X-rays
June 1974 Automatic 4-GHz frequency converter
plug-in
Sept. 1975 Automatic test system programming
language (ATLAS)
5693A
3000
3000
86634A,
86635A
5328A*
9510D,
option 100
9500D,
option 180
5061A,
option 004
5062C
3571A/
3044A/
3045A*
8495A/B
8496A/B
8495D/K
3455A*
43805
5354A
•Asterisk indicates instruments compatible with the HP interface bus (HP-IB).
June 1974 Averaging, time interval, theory
B
Apr. 1975 Band-selectable Fourier analysis
Jan. 1976 BASIC, real-time multi-user
Dec. 1974 BASIC/ 3000 timeshared computer
9510D,
option 100
9500D,
option 180
5345A*
5451B
92101A
PART 2: Subject Index (continued)
system
MPET/3000
Mar
1976
Dec.
1973
Battery-powered strip-chart recorder
7155A
Dec.
1975
Batch/spool capability for RTE systems
9600/9700
May
1975
July
1977
Beating (in APL/3000)
3000
July
1974
Bipolar power supply/amplifier
6825A-27A
Nov
1973
Nov
1973
Bit-error rate detector (150 MHz)
3761A
Mar.
1976
Bit-error rate detector (50 MHz)
3780A
Nov
1975
Feb.
1974
Bit-error rate detector,
terminal-to-terminal
1645A
Jan.
1976
Oct.
1976
Blood oxygen levels, measurement of
47201A
Nov.
1974
Breadboard, digital (logic lab)
5035T
Aug.
1974
Aug
1975
Breakpoint register (pattern analyzer)
1620A
Feb.
1975
Breakpoint register, use of
—
May
1975
Bus, HP interface. See HP-IB.
July
1977
Nov.
1975
Business calculator, pocket
HP-22
Mar.
1977
Apr.
1974
Business software for desktop
computer system
9880A
Feb.
1975
c
Aug.
1976
Sept.
1975
Cabinets, system II
Apr.
1975
July
1974
Cabinet X-ray system
43805
Dec.
1973
Cable fault locator, test desk
4913A
May
1977
Calculator algorithms, square root
—
Oct.
1974
June
1977
Calculator algorithms, trigonometric
—
1977
Nov.
1975
Calculator, business, pocket
HP-22
Dec.
1974
June
1974
Calculator/counter systems, HP
interface bus
5345A*
May
1975
Apr.
1974
Calculator mass memory system
9880A
May
1974
Calculator, pocket, programmable
HP-65
Mar.
Aug.
Nov.
July
1977
1976
1974
1977
Nov.
1975
Calculator, pocket, programmable
HP-25
Nov.
1976
Calculator, pocket, programmable
HP-67
Nov.
1976
Calculators, portable, printing
HP-91,
HP-97
Nov.
1976
Calculators, portable, programmable
Calculator, programmable, desktop.
HP-97
June
May
1975
1976
See desktop computers.
June
1977
Nov.
1975
Calculator, pocket, scientific
HP-21
June
1974
Mar.
1974
Capacitance measurements
4271A*
June
1974
Sept.
1976
Capacitance measurements
4261A*
Nov.
1973
Feb.
1975
Capacitance meter
4282A
Jan.
1977
Cardiotocograph
8030A
May
1976
May
1976
Cartridge, data, mini
—
July
1974
Mar.
1976
Cesium beam frequency reference for
Apr.
1975
severe environments
5062C
Sept.
1975
Sept.
1973
Cesium beam frequency standard,
high performance beam tube for
5061A,
June
1974
option 004
June
1974
June
1974
Channel C plug-in for 5345A counter
5353A
Mar.
1975
Apr.
1976
Chromatography, gas, microprocessor
control
5840A
July
1975
Oct.
1975
Chromatography, liquid, flow control
1010B
Apr.
1975
Dec.
1974
Chromatography, reporting integrator
June
1975
for
3380A
July
1977
Apr.
1974
Cineangiogram analysis
5693A
May
1976
Mar.
1977
Circuit design, computer-aided
Dec.
1976
(OPNODE)
92817A
May
1977
Apr.
1977
Clip for oscilloscope probing of IC's
10024A
Dec.
1976
Clip, logic
548A
Jan.
1975
Clock for systems using HP interface bus
59309A*
June
1977
Coaxial components
attenuators, dc-26.5 GHz
8495D/K
Jan.
1975
detectors, 0.01-26.5 GHz 8473C/33330C
sliding load, 2-26.5 GHz
911C
Feb.
1977
switches, dc-26.5 GHz
33311C
May
1974
Coaxial step attenuators, dc-18 GHz
8495A/B
8496A/B
July
1974
Jan.
1975
Code converter, ASCII to parallel
59301A*
Feb.
1975
Common driver circuit for guarded
May
1976
input
7047A
May
1975
Feb.
1976
Communications, data, desktop
computer
9830A
Aug.
1974
Feb.
1974
Communications, digital, error
detection
1645A
Nov.
1974
3780A
3551A,
3552A
3760A/
3761A
3790A
3745A*
4940A
5453A
3000
21MX
E-Series*
3000
Series II
62605M
21MX*
21MX-E*
Communications, digital, error
detection
Communications, telephone test set
Communications test data generator/
error detector
Communications test, microwave link
analyzer
Communications test, selective level
measurements
Communications test, transmission
impairment measuring set
Communications test, transmission
parameter analyzer
Compiler, dynamic, APL
Computer, increased performance
Computer performance improvement
Computer performance measurements
Computer power supply, switching
regulated
Computers. Also see Desktop
Computers
Computers
Computers
Computer system, BASIC/3000
timeshared MPET/3000
Computer system for voiceband data
channel measurements
Computer systems
Computer systems
Computer systems, distributed
Computer terminal, APL
Computer terminal, CRT
Computer terminal, CRT with tape
storage
Connectors, coaxial APC-3.5
Counter systems, HP interface bus
Counter, general-purpose
Counter, high-resolution, module for
5300 system
Counter, logarithmic (lab notebook)
Counter, low-cost
Counter, 1100-MHz
Counter, microwave frequency
Counter plug-in, automatic frequency
converter
Counter plug-in, third input channel
Counter/synchronizer for signal
generator
Counter/timer/DVM, universal
Counter/timer, 75-MHz universal
CRT terminal
CRT terminal, APL
CRT terminal with dual tape drives
Current tracer
Cyclic redundancy check codes (CRC)
used in signature analysis
5453A
1000*
3000 Series II
9700 Series
2641A
2640A
2644A
5345A*
5345A*
5307A
5381A-82A
5305A
5341A*
5354A
5353A
8655A
5328A*
5308A
2640A
2641A
2644A
547A
5004A
Data acquisition systems,
programmable
Data acquisition systems,
programmable
Data base management software
(IMAGE)
Data cartridge, mini
Data channel measurements, analog,
voiceband
Data channel measurements, analog,
voiceband
Data channel measurements, analog,
3050B*
3052A*
24376B,
32215A,16A
5453A
4940A
PART 2: Subject Index (continued)
Feb. 1974
Feb. 1976
Dec.
Nov.
Feb.
Aug.
Nov.
Mar.
Feb.
Apr.
Sept.
[an.
June
May
Feb.
July
Aug.
Aug.
1975
1973
1977
Aug. 1974
Nov. 1974
Aug. 1977
June 1976
Feb. 1976
June 1977
Oct. 1976
Dec. 1976
Sept. 1976
Mar. 1974
Oct. 1973
Nov. 1974
Nov. 1973
Feb. 1977
1975
1973
1976
1974
1976
1973
1975
1977
1977
Feb. 1977
1977
1975
1975
1977
Aug. 1977
Apr. 1974
Oct. 1976
June 1975
May 1976
Jan. 1975
Apr. 1977
July 1977
Mar. 1974
Sept. 1976
Feb. 1975
Apr. 1976
May 1975
Aug. 1974
Nov. 1974
July 1977
Aug. 1974
voiceband 3770A
Data channel measurements,
error analyzer
Data communications, desk-top
computer
Data domain, analog oscilloscope
Data generator, 150 MHz PRBS
Data logging systems, programmable
Delay distortion, Bell System
Delay distortion, CCITT
recommendation
Delay generator, 100-ps steps
Desktop computers
Desktop computer, data
communications
Detector, 0.01-26.5 GHz
Digital communications test, see data
channel measurements
Digital IC tester
Digital IC trouble-shooting
instruments and kits (logic probe,
logic pulser, logic clip, current tracer) 547A.548A
Digital LCR meter 4261A*
Digital LCR meter 4271A*
Digital logic analyzer 5000A
Digital logic course 5035T
Digital multimeter, hand-held 970A
Digital multimeters, low cost 3435A.3465A/B
3476A/B
Digital pattern analyzer for triggering
Digital pattern generator, communi-
cations test
Digital pattern generator, communi-
cations test
Digital pattern generator, communi-
cations test
Digital processor in a gas
chromatograph
Digital storage in a spectrum analyzer
Digital-to-analog converter for HP-IB
Digital-to-analog converter for HP-IB
Digital troubleshooting by signature
analysis
Digital voltmeter, 5V2 digit, auto-
calibrating
Digital voltmeter, fast reading, systems
Digital voltmeters, options, for
universal counter
Digital word generator, 8-bit parallel
Digital word generator, serial,
300 MHz
May 1974 Edgeline transmission in attenuators
1645A
Aug.
1974
June
1974
9830A
Sept.
1975
1740A
Aug.
1974
3 760 A
le 3051A*
Nov.
1974
4940A
May
1975
3770A
8092A
Feb.
1974
9815A/9825A*
Aug.
1976
May
1977
9830A
8473C/33330C
Nov.
1973
ita
Mar.
1976
5045A
July
1974
!, 545A.546A
Feb.
1977
1620A
3760A
3780A
1645A
5840A
3580A
59303A*
59501A*
5004A
3455A*
3437A*
5328A*
8016A*
Disc drive, 50 megabytes
Disc drive for desktop computer
Discriminator (lab notebook)
Display, CRT terminal
Display, CRT terminal, magnetic tape
Display, numeric for HP interface bus
Displays, small solid-state
alphanumeric
Display station, APL
Dissipation factor measurements
Dissipation factor measurements
Dissipation factor measurements
Distance measurements, surveying
Distortion measurements, amplitude
Distortion measurements, amplitude,
phase, envelope delay, nonlinear
Distributed computer systems
Dragalong (in APL/3000)
Dropouts
Oct. 1976 Ear oximeter
8084A/
8080A
7920A
9880A
2640A
2644A
59303A*
HDSP-2000
2641A
4271A*
4261A*
4282A
3810A
5453A
4940A
9700 Series
3000
4940A
47201A
Aug. 1976
Dec. 1973
Dec. 1976
Nov.
Jan.
Feb.
Oct.
Mar.
Apr.
Feb.
June
Sept.
June
Nov.
July
Apr.
June
June
Mar.
Aug.
Sept.
1976
1977
1974
1975
1976
1975
1975
1974
1975
1974
1973
1974
1975
1974
1974
1976
1974
1973
Mar. 1975
May 1975
Nov. 1976
Aug. 1974
Apr. 1976
Dec. 1974
Nov. 1973
July 1975
Educational TV receiver
Electronic counter, general-purpose
Enclosures, electronic instrument
Envelope delay distortion
measurements
Envelope delay distortion
measurements
Envelope delay distortion
measurements
Error analyzer, data transmissions
Error-correcting memory 3000
Error detection by transition counting
and signature analysis
Error detector, communications test
(150 MHz)
Error detector, communications test
(50 MHz)
Exposure control for X-ray system
Extending a digital multimeter's range
8495A/B
8496A/B
5345A*
4940A
3 7 70 A
5453A
1645A
Series II
5004A
3761A
3 780 A
43805
3435A,
3465A/B
3476A/B
Fault control memory 3000 Series II
Fault locator, test desk 491 3 A
Fault (low-impedance) localization in
digital logic circuits 547A
FET, GaAs for microwaves HFET-1000
Fetal monitoring 8030A
Filters, VHF coaxial (lab notebook) —
Flow control in liquid chromatography 1010B
FM, calibrated, signal generator 8654B
Fourier analysis, band selectable 5451B
Fourier analyzer 5451B
Frequency converter plug-in 5354A
Frequency counter, 4.5 GHz 5341A*
Frequency counter 5 345 A*
Frequency counter, high-resolution
module for 5300 system 5307A
Frequency counters, low cost 5381A.82A
Frequency counter, 1100-MHz 5305A
Frequency measurements, reciprocal 5345A*
Frequency profile measurements,
pulsed RF 5345A*
Frequency reference, cesium beam 5062C
Frequency shift measurements 4940A
Frequency standard, high-performance
cesium beam 5061A,
option 004
Function generator, dual source 3312A
Function generator, low distortion 3551A/3552A
GaAs FET amplifier, chips
Gain hits measurements
Gas chromatograph,
digitally-controlled
Gas chromatograph reporting
integrator
Generator, digital, 150 MHz
Generator, signal, phase modulated
July 1975 Generator, signal, synthesized 2.6 GHz
Generators, pulse; see pulse generators
Generators, word; see word generators
Oct. 1975 Gradient programming, liquid
chromatography
July 1976 Group delay detector
Aug. 1974 Group delay measurements
Nov. 1974 Group delay measurements
HFET 1000
4940A
5840A
3380A
3760A
86634A,
86635A
86603A
1010B
8505A*
4940A
3770A
PART 2: Subject Index (continued)
May
1975
Group delay measurements
5453A
Dec.
1976
H
Dec.
1975
Jan.
1977
Heart-rate monitoring, fetal
8030A
Aug.
1975
Feb.
1975
High capacitance meter
4282A
May
1977
Sept.
1973
High-performance cesium beam tube
5061A,
option 004
Aug.
1974
Nov.
1973
High-resolution counter module for
May
1975
5300 system
5307A
Nov.
1974
Feb.
1975
High-sensitivity X-Y recorder
7047A
May
1975
June
1976
HPL, desktop computer language
9825A*
July
1974
Jan.
1975
HP-IB analyzer
59401A*
Feb.
1977
Jan.
1975
HP-IB, current status
—
June
1974
HP-IB, counter systems
5345A*
Nov.
1973
Jan.
1975
HP-IB systems
HP interface bus, see HP-IB
Sept.
1973
Apr.
1976
Horizontal distance and angle
measurements
3810A
1
Feb.
Jan.
1976
1974
Oct.
1976
IC tester, digital
5045A
May
1976
Oct.
1976
IC testing, economic considerations
5045A
June
1976
Dec.
1976
IC troubleshooting instruments and
kits
545A.546A,
May
1976
547A,548A
Apr.
1974
July
1974
IMAGE
24376B,
Feb.
1977
32215A-16A
Oct.
1974
June
1976
Impact printer
9871A
Sept.
1976
Aug.
1974
Impulse noise measurements
4940A
Aug.
1977
May
1975
Impulse noise measurements
5453A
Aug.
1974
Oct.
1976
Incoming inspection, digital ICs
5045A
Apr.
1977
Mar.
1974
Inductance measurement
4271A*
Aug.
1975
Sept.
1976
Inductance measurement
4261A*
Jan.
1977
July
1974
Information management software
24376B,
Oct.
1974
32215A-16A
Mar.
1977
Mar.
1977
Integrated-circuit technology,
viewpoint
Feb.
1975
Dec.
1974
Integrator, chromatograph, reporting
3380A
May
1974
Jan.
1975
Interface, ASCII, for 5300-series
June
1977
instruments
5312A*
Sept.
Nov.
1975
1975
Interface bus, see HP-IB.
Nov.
1976
Jan.
1974
Interferometer, straightness
5526A,
option 30
July
1975
Apr.
1974
Inventory control system, desk-top
computer
9880A
Dec.
1974
J
Aug.
1976
«
Nov.
1973
L
Feb.
1977
Feb.
1977
July
1977
Language, computer, APL 3000 Series II
Jan.
1976
Sept.
1975
Language, computer, ATLAS 9500D,9510D
June
1976
Language, desktop computer, HPL
9825A*
Aug.
1976
Jan.
1974
Laser interferometer, straightness
5526A,
option 30
Jan.
1976
Feb.
1976
Laser transducer system
5501A*
Sept.
1976
LCR meter, automatic, digital
4261A*
Mar.
1974
LCR meter, 1 MHz automatic, digital
4271A*
July
Nov.
Mar.
June
Apr.
1977
LED displays, alphanumeric
HDSP-2000
1976
July
1976
Line stretcher, electronic
8505A*
1974
Oct.
1975
Liquid chromatography, flow control
1010B
1975
June
1977
Load, sliding, 2-26.5 GHz
911C
1976
May
1976
Logarithmic counter (lab notebook)
—
Mar.
Aug.
May
Aug.
1974
1974
Oct.
1973
Logic analyzer
5000A
Dec.
1976
Logic clip, multifamily
548A
1975
Nov.
1974
Logic lab
5035T
1974
Dec.
1976
Logic probe, multifamily
545A
May
1975
Dec.
1976
Logic pulser, multifamily
548A
Nov.
1975
Aug.
1975
Logic state analyzer
1600S
Jan.
1974
Logic state analyzer
1601L
Jan.
1977
Logic state analyzer for
microprocessors
1611A
Dec.
1975
Logic-state analyzers, serial-to-parallel
conversion
Logic test, analog oscilloscope
Logic trigger
Logic troubleshooting by signature
analysis
Loss measurements
Loss measurements
Loss measurements
Loss measurements
10254A
1740A
1230A
5004A
4940A
5453A
3770A
3551A/3552A
5381A-82A
3435A,
3465A/B.3476A/B
Low-frequency measurements with
high-resolution counter 5307A
Low-frequency spectrum analyzer 3 5 80 A
Low-cost counters
Low-cost digital multimeters
M
5501A*
5526A
9815A/
9825A*
2644A
9880A
3455A*
21MX*
4261A*
7920A
1600 A
1611A
21MX
1000*
Machine positioning laser transducer
Machine tool calibration
Magnetic tape cartridge, mini
Magnetic tape minicartridge,
in desk-top computer
Magnetic tape storage, in CRT terminal
Mass memory for desk-top computer
Math functions in a digital voltmeter
Memory, semiconductor
Meter, LCR digital
MFM code, for magnetic recording
Microcircuit TV receiver
Micro-CPU chip (MC 2 ), CMOS/SOS
Microprocessors, logic-state analysis of
Microprocessors, logic-state analyzer for
Microprogrammable central processor
Microprogramming aids
Microprogramming, performance
improvement by —
Microwave attenuators, dc-18 GHz 8495 A/B-96A/B
Microwave attenuators, dc-26.5 GHz 8495D/K
Microwave counter, 4.5 GHz 5341A*
Microwave link analyzer, 140-MHz IF 3 790 A
Microwave sweep oscillators, 86242C,
5.9-12.4 GHz 86250C
Modulator, phase, for signal generator 86634A,
86635A
MPET/3000, multiprogramming
executive for timesharing 32010A
Multilingual computer systems 3000 Series II
Multimeter, digital, hand-held 970A
Multimeters, digital, low cost 3435A,
3465A/B,3476A/B
Multimeters, extending the ranges of —
Multiplexed communications test,
frequency division 3745A*
Multiprogramming computer
systems 3000 Series II
Multi-user real-time BASIC —
N
Network analyzer, 0.5-1300 MHz 8505A*
Networks, computer 9700 Series
Network measurements, 2-18 GHz —
NMOS LSI processor 9825A*
Noise, types, in signal generators 8654A
Noise measurements, telephone 4940A
Noise measurements, telephone 5453A
Nonlinear distortion measurements 4940A
Nonlinear distortion measurements 5453A
Nonlinear distortion measurements
on microwave links 3790A
Operating systems, real-time 92001 A,
PART 2: Subject Index (continued)
Mar. 1977
Mar. 1977
Nov. 1976
Mar. 1975
Dec. 1975
Sept. 1974
Dec. 1974
Apr. 1977
Feb. 1974
Aug. 1975
Oct. 1973
Dec. 1975
Sept. 1976
Oct.
Oct.
Nov.
Mar.
Aug.
Aug.
May
Aug.
Aug.
May
July
June
June
Nov.
May
Nov.
Nov.
Nov.
Nov.
Dec.
Sept.
Oct.
Oct.
July
June
July
June
Dec.
1976
1976
1973
1976
1974
1974
1975
1974
1974
1975
1975
1974
1974
1975
1974
1976
1975
1975
1976
1973
1974
1975
1975
1976
1977
1974
1977
1973
Apr. 1975
June
Dec.
Jan.
Jan.
Nov.
Apr.
Oct.
June
Apr.
May
Nov.
Nov.
June
Oct.
July
Sept.
June
May
1976
1974
1975
1975
1976
1977
1975
1976
1977
1974
1976
1975
1976
1976
1977
1975
1976
1977
(RTE-II, RTE-III)
OPNODE
Optimization, circuit, computer aided
Oscillators, sweep, 5.9-12.4 GHz
Oscillator, sweep, 2-18 GHz
Oscilloscope, 100 MHz
Oscilloscope, 275 MHz
Oscilloscope, dual-delayed sweep,
microprocessor-controlled,
numeric display
Oscilloscope probes, miniature
Oscilloscopes, low-cost, dc-15 MHz
Oscilloscope triggering on
digital events
Oscilloscope, used with logic analyzer
Oscilloscope, used with logic-state
analyzer
Oscilloscope, variable persistence/
storage 1741 A
Oximeter 47201A
Oxygen levels in blood, measurement of 47201A
PCM systems, error detection 3760A/3761A
PCM systems, error detection 3780A
Peak-to-average ratio measurements
on voiceband data channels
Phase distortion measurements
Phase distortion measurements
Phase hits measurements
Phase jitter measurements
Phase jitter measurements
Phase-modulated signal generator
plug-in; also, applications for
Plug-in, automatic frequency converter
Plug-in, channel C
Pocket calculator, business
Pocket calculator, card programmable
Pocket calculator, card programmable
Pocket calculator, key programmable
Pocket calculator, scientific
Portable calculators
Portable strip-chart recorder
Power meter
Power meter, digital
Power sensor, high-sensitivity
Power splitter, 3-way
Power supplies, 200W, wide range
Power supply/amplifier, bipolar
Power supply programmer (HP-IB)
Power supplies, switching regulator.
modular, 4-28V, 300 W
Power supply, switching regulated,
5V, 500 W
Printer, impact
Printer-plotter for chromatographs
Printer, thermal, for instruments
Printer with clock option
Printing calculators
Probes, oscilloscope, miniature
Probes, time interval
Processor, NMOS LSI
Processor, CPU, CMOS/SOS
Programmable calculator, pocket-sized HP-65
Programmable calculator, pocket-sized HP-67
Programmable calculator, pocket-sized HP-25
92060A
92817A
Mar.
1976
ed 92817A
86242C,
86250C
Nov.
1973
86290A
1740A
1720A
June
Mar.
1974
1974
1722A
Oct.
1973
10017Aetal.
1220A/1221A
10250/
Aug.
Aug.
1977
1977
1230A/1620A
zer 5000A
Sept.
1974
1740A
July
1974
4940A
4940A
5453A
4940A
4940A
5453A
86634A,
86635A
5354A
5353A
HP-22
HP-65
HP-67
HP-25
HP-21
HP-91.HP-97
7155A
435A
436A*
8484A
11850A/B
6002A*
6825A-27A
59501A*
62600J
62605M
9871A
3380A
5150A*
5150A*
HP-91.HP-97
10017Aet al.
5363A*
9825A
Programmable computer, desk-top 9815A/9825A*
Programmable IC tester 5045A
Programming language, APL 3000
Programming language ATLAS 9500D.9510D
Programming language HPL 9825A*
Pseudorandom binary sequences
(PRBS) for signature analysis 5004A
Jan.
Jan.
Mar.
Nov.
Nov.
Aug.
Jan.
Jan.
Jan.
Dec.
Mar.
Mar.
Mar.
July
Mar.
July
Oct.
May
Apr.
Aug.
June
Apr.
July
Mar.
Oct.
Sept.
May.
Dec.
May
June
1974
1976
1977
1974
Dec. 1975
Dec. 1973
Feb. 1975
Jan. 1975
Mar. 1974
Mar. 1975
Dec. 1975
Dec. 1975
1974
1974
1975
1975
1976
1976
May 1977
1974
1976
1974
1975
1976
1975
1976
1977
1977
1974
May 1975
1977
1976
1976
1977
1976
1973
1975
1975
1977
1974
Pseudorandom binary sequences
(50 MHz) for testing digital
communications
Pseudorandom binary sequences ■
(150 MHz) for testing digital
communications
Pulsed RF frequency measurements
Pulse generator, 20 MHz,
counted burst
Pulse generator, 50 MHz, 16V,
counted burst
Pulse generator, 1 GHz
Pulse generator, dual-output with
Vz frequency 8092A/8080A
Pulse generator, variable risetime to 1 ns 8082A
3780A
3790A
5345A*
8011A
8015A
8080-Series
QUERY
24376B,
82215A-6A
R
Ray-trace program
Real-time BASIC
Real-time executive operating system
Real-time executive systems,
in distributed networks
Real-time executive systems,
RTE-II, RTE-III
Recorder, strip-chart, portable
Recorder, X-Y, high-sensitivity
Relay actuator for HP interface bus
Resistance measurements
RF plug-in, 2-18 GHz
RTE-II real-time executive system
RTE-III real-time executive system
for large memories
92101A
1000*
9700 Series
92001A,92060A
7155A
7047A
59306A*
4271A*
86290A
92001A
92060A
Satellite computer systems 9601,9610
Satellite-relayed TV —
Scanner for calculator-based systems 3495A*
Scanner option for printer 5150A*
Selective level measuring set 3 745 A*
Serial-to-parallel conversion for
logic-state display 102 54 A
Servicing digital equipment by
signature-analysis circuits 5004A
Signal generator, 10-520 MHz 8654A
Signal generator, calibrated FM 8654B
Signal generator noise specifications 8654A
Signal generator, phase modulated 86635A
Signal generator synchronizer/counter 8655A/
8654B
Signal generator, synthesized 2.6 GHz 86603 A
Signal-level reference (lab notebook) —
Signature analysis 5004A
Silicon-on-sapphire (SOS), CPU chip —
Single-frequency interference
measurements 4940A
Single-frequency interference
measurements 545 3 A
Sliding load, 2-26.5 GHz 911C
Slope distance measurements 3810A
Source, RF, tracking 8505A*
Sparse Y matrix, in circuit analysis 9281 7A
Spectrophotometry applied to blood
oxygen measurement 47201A
Spectrum analyzer, 5 Hz to 50 kHz 3580A
Spectrum analyzer, 10 Hz to 13 MHz 3571 A/
3044A/3045A*
Spooling, in RTE systems —
Square root algorithm, calculator —
State-machine design 5345A*
PART 2: Subject Index (continued)
Sept.
1976
Jan.
1974
Dec.
1973
July
Apr.
1977
1976
Nov.
1976
Mar.
Jan.
Apr.
1975
1975
1975
Dec.
1973
June
Mar.
1977
1976
July
Nov.
Feb.
1975
1974
1977
May
Nov.
1976
1974
Aug.
1974
May
1975
Feb.
1974
Dec.
1974
Jan.
1976
May
1975
Aug.
Feb.
1974
1976
June
July
May
Dec.
July
1975
1977
1976
1973
1976
Oct.
Feb.
1976
1977
Nov.
Sept.
Apr.
Dec.
1976
1974
1974
1975
June
Oct.
Dec.
1974
1975
1974
Feb.
July
1977
1975
Storage/ variable persistence
oscilloscope 1741 A
Straightness interferometer 5526A,
option 30
Strip chart recorder, portable,
battery-powered 7155A
Structured programming, APL/3000 3000
Surveying, distance and angle
measurements 3810A
Sweep oscillators, 5.9-12.4 GHz 86242C,
86250C
Sweep oscillator, 2-18 GHz 86290A
Switch, VHF, for HP interface bus 59307A*
Switching regulated power supply,
5V, 500W 62605M
Switching regulated power supplies,
modular, 4-28V, 300W 62600J
Switches, microwave, dc-26.5 GHz 33311C
Synchronizer/counter for signal
generator 8655A
Synthesized signal generator, 2.6 GHz 86603 A
Systems, distributed computer 9700 Series
Systems voltmeter, fast reading 3437A*
Tape cartridge, mini —
Telephone data channel
measurements, analog 3770A
Telephone data channel
measurements, analog 4940A
Telephone data channel
measurements, analog 5453A
Telephone data channel
measurements, error analysis 1645 A
Telephone measurements,
loop-holding device 3770A
Telephone measurements,
multichannel systems 3745A*
Telephone measurements,
transmission test 3551A/3552A
Television by satellite, receiver for —
Terminal (calculator),
data communications
Terminal, computer, CRT
Terminal, CRT, APL
Terminal, CRT, with dual tape drives
Test desk cable fault locator
Test sets, network analysis
Tester, digital IC
Testing a multimeter abusively
9830A
2640A
2641A
2644A
4913A
8502A/
8503A
5045A
3435A,
3465A/B.3476A/B
HP-91, HP-97
435A
Thermal printer, calculator
Thermocouple power meter
Thermometer, platinum, digital 2 802 A
Thick-film hybrid oscilloscope
amplifier 1740A
Time-interval averaging —
Time interval probes 5363A*
Time interval measurements,
very short 1722 A
Time-related voltage measurements 3437A*
Timer/counter/DVM, universal 5328A*
Apr. 1975
Dec. 1974
Jan. 1975
Apr. 1976
Feb. 1976
Aug. 1974
Nov. 1976
Apr. 1975
May 1977
Aug. 1974
May 1975
Aug. 1975
June 1977
May 1977
July 1975
Apr. 1975
Apr.
Feb.
Sept.
Apr.
Jan.
Aug.
Aug.
July
May
Aug.
Nov.
July
1974
1977
1976
1976
1975
1977
Mar. 1977
1976
1977
1975
1974
1974
1975
Feb. 1977
Aug. 1977
Aug. 1975
July 1974
Feb. 1975
Mar. 1975
Apr. 1976
Timer/counter, 75-MHz universal 5308A
Timeshared system, BASIC/3000 MPET/3000
Timing generator for HP interface bus 59308A*
Total station 3810A
Transducer, laser 5501A*
Transient measurements on
voiceband data channels 4940A
Transistor, FET GaAs microwave HFET 1000
Transistor process, 5-GHz —
Transition counting algorithms 5004A
Transmission impairment
measuring set 4940A
Transmission parameter analyzer 5453A
Trigger probes/recognizers 10250/
1230A/1620A
Trigonometric algorithms, calculator —
Troubleshooting logic circuits by
signature analysis 5004A
u
Universal counter/timer/DVM 5328A*
Universal counter/timer, 75-MHz 5308A
Ventricular function, analysis of
cineangiograms 5693A
Voltmeters, digital 3455A*,3437A*,
3435A,3465A/B,3476A/B
Variable-persistence/storage
oscilloscope 1741 A
Vertical distance measurements 3810A
VHF switch for HP interface bus 59307A*
Vibrations, mechanical analogy
for servo system 7920A
Viewpoints, integrated-circuit
technology —
Virtual-memory computer systems 3000 Series II
Virtual workspace, APL/3000 3000
Voiceband data channel analyzer 5453A
Voiceband data channel
measurements, analog 4940A
Voiceband data channel
measurements, analog 3770A
Voltmeter options for
universal counter 5328A*
w
Waveform measurements with digital
voltmeter 343 7 A*
Word generator, 300 MHz 8084A
Word generator, multichannel 8016A*
X-ray system for bench use 43805
X-Y recorder, high-sensitivity 7047A
YIG-tuned oscillator —
z
Zenith angle measurements 3810A
PART 3: Model Number Index
Model Instrument
Month/Year
HP-22
HP-25
HP-21 Calculator
Nov. 1975
HP-65
*21MX Computers
Oct. 1974
HP-67
*21MXE-Series Computers
Mar. 1977
HP-91
HP-97
"Asterisk indicates instruments compatible with the HP interface bus (HP-IB).
Calculator Nov. 1975
Calculator Nov. 1975
Programmable Pocket Calculator May 1974
Programmable Pocket Calculator Nov. 1976
Printing Portable Calculator Nov. 1976
Programmable Printing
Portable Calculator Nov. 1976
Part 3: Model Number Index (continued)
435A
*436A
545A
546A
547A
548A
911C
970A
HFET-1000
*1000-Series
1010B
1220A/1221A
1230A
1600A/S
1601L
1607A
1611A
1620A
645A
1720A
1722A
1740A
1741A
HDSP-2000
IMAGE/2000
2640A
2641A
2644A
2802A
3000 Series II
APL/3000
IMAGE/3000
MPET/3000
*3044A
* 3045 A
*3050B
*3051A
*3052A
3312A
3380A
3435A
*3437A
*3455A
3465A/B
3476A/B
*3495A
3551A
3552A
*3571A
3580A
*3745A/B
3760A/3761A
3770A
3780A
3790A
3810A
*4261A
*4271A
4282A
4913A
4940A
5000A
5004A
5035T
5045A
5061A opt. 004
5062C
Power Meter
Power Meter
Logic Probe
Logic Pulser
Current Tracer
Logic Clip
Sliding Load
Probe Multimeter
GaAs FET
Small Computer Systems
Liquid Chromatograph
Oscilloscopes, 15 MHz
Logic Trigger
Logic State Analyzer
Logic State Analyzer
Logic State Analyzer
Logic State Analyzer
Pattern Analyzer
Data Error Analyzer
Oscilloscope, 275 MHz
Oscilloscope, dual-delayed sweep
Oscilloscope, 100 MHz
Variable Persistence/Storage
Oscilloscope
Solid-State Alphanumeric Display
Data Base Management System
Interactive Display Terminal
APL Display Station
CRT Terminal with Magnetic
Tape Storage
Platinum-Resistance Thermometer
Computer System
A Programming Language
Data Base Management System
Multiprogramming Executive
Spectrum Analyzer,
lOHzto 13MHz
Automatic Spectrum Analyzer
Automatic Data
Acquisition System
Data Logging System
Programmable Data
Acquisition System
Function Generator
Chromatograph Integrator
Digital Multimeter
System Voltmeter
Digital Voltmeter
Digital Multimeter
Digital Multimeter
Scanner
Transmission Test Set
Transmission Test Set
Tracking Spectrum Analyzer
Spectrum Analyzer, 5Hz-50kHz
Selective Level Measuring Set
Data Generator/Error Detector
Amplitude/Delay
Distortion Analyzer
Pattern Generator/Error Detector
Microwave Link Analyzer
Total Station
LCR Meter
LCR Meter
High-Capacitance Meter
Test Desk Fault Locator
Transmission Impairment
Measuring Set
Logic Analyzer
Signature Analyzer
Logic Lab
IC Tester
High-Performance Cesium Beam
Standard
Cesium Beam Frequency Reference
Sept.
1974
*5150A
Oct.
1975
5300B
Dec.
1976
5305A
Dec.
1976
5307A
Dec.
1976
5308A
Dec.
1976
*5312A
June
1977
*5328A
Nov.
1973
*5341A
Nov.
1976
*5345A
Mar.
1977
5353A
Oct.
1975
5354A
Feb.
1974
Aug.
1975
*5363A
Aug.
1975
5381A/5382A
Jan.
1974
5451B
Aug.
1975
5451B
Jan.
1977
Aug.
1975
5453A
Feb.
1974
5468A
Sept.
1974
*5501A
Dec.
1974
5526A opt. 30
Dec.
1975
5693A
5840A
Sept.
1976
*6002A
Apr.
1977
6825A/6A/7A
July
1974
7047A
June
1975
7155A
July
1977
7920A
8011A
May
1976
8015A
Apr.
1974
*8016A
Aug.
1976
8030A
July
1977
8080-Series
July
1974
8082A
Dec.
1974
8473C
8481A et al.
May
1975
8484A
May
1975
8495A/B,
8496A/B
Jan.
1975
8495D/K
Feb.
1977
8502A
Feb.
1977
8503A
Mar.
1975
*8505A
Dec.
1974
8620A
Feb.
1977
8654A
Feb.
1977
8654B
Feb.
1977
8655A
Feb.
1977
8660C
Feb.
1977
Jan.
1975
9500D opt. 180
May
1975
9510D opt. 100
May
1975
9601/9610
May
1975
9700-Series
Sept.
1973
*9815A
Jan.
1976
*9825A
Nov.
1973
*9830A
9871A
Nov.
1974
9880A/B
Mar.
1976
Nov.
1975
10017Aetal.
Apr.
1976
10250-Series
Sept.
1976
10254A
Mar.
1974
11850A
Feb.
1975
Dec.
1973
24376B
Aug.
1974
32010A
Oct.
1973
32105A
May
1977
32215A
Nov.
1974
Oct.
1976
32216A
Sept.
1973
33311C
Mar.
1976
33321A/B
Thermal Printer Jan. 1975
8-Digit Mainframe Apr. 1975
1100-MHz Frequency Counter Apr. 1975
High-Resolution Counter Nov. 1973
75-MHz Universal Timer/Counter Apr. 1975
ASCII Interface Jan. 1975
Universal Counter July 1975
Frequency Counter Sept. 1975
Electronic Counter June 1974
Channel C Plug-In June 1974
Automatic Frequency Converter
0.015-4.0 GHz June 1974
Time Interval Probes Oct. 1975
Frequency Counters July 1974
Fourier Analyzer Feb. 1975
Fourier Analyzer with BSFA
Capability Apr. 1975
Transmission Parameter Analyzer May 1975
Transponder May 1975
Laser Transducer System Feb. 1976
Straightness Interferometers Jan. 1974
Angio Analyzer Apr. 1974
Gas Chromatograph Apr. 1976
DC Power Supply, 200W June 1977
Bipolar Power Supply/ Amplifiers July 1974
X-Y Recorder Feb. 1975
Portable Strip-Chart Recorder Dec. 1973
Disc Drive Aug. 1977
Pulse Generator, 20 MHz Mar. 1974
Pulse Generator, 50 MHz Oct. 1973
Word Generator Aug. 1975
Cardiotocograph Jan. 1977
High-Speed Pulse/Word Generator Aug. 1977
Pulse Generator, 250 MHz Sept. 1974
Coaxial Detector, 0.01-26.5 GHz June 1977
Power Sensors Sept. 1974
Power Sensor, High Sensitivity Oct. 1975
Step Attenuators, dc-18 GHz May 1974
Step Attenuators, dc-26.5 GHz June 1977
Transmission and Reflection
Test Set July 1976
S-Parameter Test Set July 1976
Network Analyzer, 0.5-1300 MHz July 1976
Sweep Oscillator Mar. 1975
Signal Generator, 10-520 MHz Mar. 1974
Signal Generator with FM Mar. 1976
Synchronizer/Counter Mar. 1976
Synthesized Signal Generator
Mainframe July 1975
ATLAS Compiler and Processors Sept. 1975
ATLAS Compiler and Processors Sept. 1975
Satellite Computer Systems Nov. 1974
Distributed Computer Systems Nov. 1974
Desktop Computer June 1976
Desktop Computer June 1976
Desktop Computer (application of) Feb. 1976
Impact Printer June 1976
Desktop Computer Mass
Memory System Apr. 1974
Miniature Oscilloscope Probes Apr. 1977
Trigger Probes Aug. 1975
Serial-to-Parallel Converter Dec. 1976
Three-Way Power Splitter,
0.5-1300 MHz July 1976
IMAGE/2000 Data Base
Management System July 1974
MPET/3000 Operating System Dec. 1974
APL/3000 Subsystem July 1977
IMAGE/ 3000 Data Base
Management System July 1974
QUERY/ 3000 Data Base
Inquiry Facility July 1974
Microwave Switch, dc-26.5 GHz June 1977
Step Attenuators, dc-18 GHz May 1974
Part 3: Model Number Index (continued)
33321D/K
Step Attenuators, dc-26.5 GHz
June
1977
62605M
33330C
Coaxial Detector, 0.01-26.5 GHz
June
1977
43805
X-Ray System
July
1974
86242C,
47201A
Oximeter
Oct.
1976
86250C
*59301A
ASCII-Parallel Converter
Jan.
1975
86290A
*59303A
Digital-to-Analog Converter
Jan.
1975
86603A
*59304A
Numeric Display
Jan.
1975
86634A
*59306A
Relay Actuator
Jan.
1975
86635A
*59307A
VHF Switch
Jan.
1975
91700Aetal
*59308A
Timing Generator
Jan.
1975
92001A
*59309A
ASCII Digital Clock
Jan.
1975
92001B
*59401A
Bus System Analyzer
Jan.
1975
92060A
*59501A
Isolated D-A/Power
92060B
Supply Programmer
June
1977
92061A
62604J et al.
Switching Regulated Modular
92101A
Power Supplies
Dec.
1973
92817A
500W Switching Regulated
Power Supply Apr. 1975
RF Plug-Ins for 8620C Sweep
Oscillator Nov. 1976
2-18 GHz RF Plug-In. Mar. 1975
1-2600 MHz RF Section July 1975
PM Modulation Section July 1975
FM/PM Modulation Section July 1975
Distributed Computer Systems Nov. 1974
RTE-II Real-Time Executive System Dec. 1975
RTE-II Real-Time Executive System Mar. 1977
RTE-III Real-Time Executive System Dec. 1975
RTE-III Real-Time Executive System Mar. 1977
RTE Microprogramming Package Mar. 1977
Real-Time BASIC Subsystem Jan. 1976
OPNODE Mar. 1977
PART 4: Author Index
Author A
Month/Year
Corya, Bruce S.
July
1975
Forbes, Bert E.
Apr.
1977
Coster, John H.
Jan.
1976
Foster, Tony E.
Apr.
1974
Adler, Robin
Oct.
1973
Courtin, Erich
Jan.
1977
Fowles, Richard G.
Aug.
1974
Ainsworth, Gerald
Oct.
1976
Crawford, Thomas
Nov.
1973
Fox, Kenneth A.
Dec.
1975
Aken, Michael B.
May
1975
Crow, George
June
1975
Frankenberg, Robert J.
Oct.
1974
Anzinger, George A.
Dec.
1975
Frederick, Wayne
July
1976
Arnold, David
May
1976
D
Frohwerk, Robert A.
May
1977
Ashkin, Peter B.
Apr.
1977
G
Atchley, Robert L.
May
1975
Dack, David G.
Jan.
1976
Averett, Linda W.
Dec.
1975
Dalichow, Rolf
July
1976
Gadol, Adele M.
Dec.
1975
B
Damon, Noel E.
Aug.
1974
Gammill, Lawrence A.
Apr.
1977
Daniels, Jerry W.
May
1975
Globas, Gert
Sept
1974
Bailey, Paul W.
June
1977
Danielson, Dan D.
Mar.
1975
Gookin, Albert
Feb.
1977
Baker, Mark
Oct.
1973/
Deaver, David K.
May
1975
Gordon, David E.
Dec.
1976
Oct.
1976
Dickey, Shane
Nov.
1974
Gordon, Philip
Oct.
1974
Baldwin, Richard R.
Jan.
1974
Dickinson, Peter D.
Nov.
1976
Gorin, Joseph M.
Feb.
1977
Barney, Dick B.
June
1976
Diehl, Van
Dec.
1975
Grady, Robert B.
Sept.
1975
Barker, Roy D.
Feb.
1977
Dietrich, Harold E.
Jan.
1975
Graham, Thomas R.
Dec.
1973
Barraclough, Hal
Dec.
1974
DiFrancesco, Mauro
Apr.
1975
Grote, Barbara E.
Jan.
1974
Basawapatna, Ganesh
Mar.
1975
Dikeman, Peter
Apr.
1974
Guest, David H.
Nov.
1974/
Beckwith, John F.
Dec.
1976
Dilman, Richard
Feb.
1974
Dec.
1974
Best, Allan I.
Dec.
1975
DiPietro, David M.
Apr.
1975
Bilen, Len
Apr.
1976
Dresch, Donald A.
Aug.
1974
H
Blazek, Otakar
Bologlu, Ali
June
June
Sept.
July
1975
1974/
1975
Drake, Harris Dean
Doub, James A.
Dudley, B. William
Mar.
June
Dec.
1977
1975
1973
Hahn, Kathleen F.
Hale, William L.
Mar.
Sept.
1977
1973
Botka, Julius
1976
Dudley, Robert L.
Nov.
1973
Hall, James A.
Aug.
July
Oct.
Sept.
July
1974/
Bradley, Havyn E.
Brewster, John L.
Bronson, Barry
Apr.
July
Nov.
Dec.
1974
1974
1974/
Duerr, Jeffrey R.
Dupre, John J.
E
Feb.
Mar.
1974
1975
Hammons, Richard L.
Hardage, P. Kent
Harkins, Daniel R.
1975
1974
1974
1976
1976
Harland, David A.
Jan.
1974
Buesen, Jiirgen
Aug.
1975
Eads, William D.
June
1976
Harms, Dennis W.
Nov.
1976
Bullock, Michael L.
Apr.
1976
Eastham, Terry
June
1975
Harrison, Joel
Harrison, Van
Aug.
Sept.
1977
Bump, Robert B.
June
1976
Eberle, Volker
Aug.
1977
1976
c
Edwards, Allen P.
Oct.
1975
Hashimoto, Satoru
Sept.
1976
Egbert, William E.
Nov.
1976/
Hay, Robert R.
Mar.
1974
Campbell, John W.
Dec.
1975
May
1977/
Hayes, Thomas J.
Oct.
1976
Carlson, James E.
Feb.
1976
June
1977
Heger, Charles E.
Mar.
1976
Chambers, Donald R.
June
1977
Eggert, Rainer
Mar.
1974
Heinzl, Johann J.
Aug.
1974
Chan, Anthony Y.
Dec.
1976/
Elward, John S.
Oct.
1974
Hender, Thomas A.
Nov.
1975
May
1977
Enlow, Carl Jr.
Mar.
1975
Hentschel, Christian
Aug.
1977
Chance, Geoffrey W.
June
1976
Estes, Marvin F.
Apr.
1977
Hernday, Paul R.
Mar.
1975
Chen, Philip
July
1976
F
Hickenlooper, F. Timothy
June
1976
Christensen, Svend
Nov.
1975
Hines, Jack L.
Apr.
1977
Christopher, Chris J.
Apr.
1974/
Falke, Reinhard
Oct.
1973
Hohmann, Hans-Giinter
Feb.
1974
June
1976
Farnbach, William A.
Jan.
1974
Hood, James M.
Dec.
1973/
Chu, Alejandro
Mar.
1975
Farrington, David
Apr.
1977
Aug.
1977
Chu, David C.
June
1974
Felsenstein, Ronald E.
June
1974
Horner, James F.
July
1975
Clifford, Douglas M.
June
1976
Fichter, George
Nov.
1975
House, Charles H.
Dec.
1975
Cline, Stephan G.
May
1975
Finch, Carolyn M.
Apr.
1977
Huff, Donald W.
Feb.
1975
Collison, Robert R.
Mar.
1976
Finch, William R.
Sept.
1975
Hyatt, Ronald C.
Sept.
1973/
Cornish, Eldon
Sept.
1974
Fischer, Walter A.
Dec.
1974
Mar.
1976
Cook, Michael J.
Nov.
1975
Fong, Arthur
Aug.
1974
Hyde, John W.
June
1977
Part 4: Author Index (continued)
Ingman, Eric M.
Inhelder, Allen F.
Jackson, William D.
Jackson, Weldon H.
Jacobs, Jacob R.
Jager, Clifford A.
Jekat, Hans J.
Jensen, Ronald C.
Jeppsen, Bryce E.
Jeremiasen, Robert
Johnson, Daniel E.
Johnson, Lawrence P.
Johnson, Lee
Johnston, Ronald L.
Joly, Robert
Juneau, H. Mac
K
Kappler, Wolfgang
Keever, Jerome
Ketelsen, Erhard
Kim, Young Dae
Kirkpatrick, George R.
Kmetovicz, Ronald E.
Knorpp, Billy
Krauss, Giinter
Kuhlman, Louis J. Jr.
Kushnir, S. Raymond
L
Laing, Virgil L.
Lamy, John
Lane, Arthur B.
Lane, Thomas A.
Langguth, Alfred
Larsen, James
Lawson, William S.
Lee, Richard T.
Leong, Warren W.
Link, Horst
Liu, Chi-ning
Loughry, Donald C.
Luehman, Kent
M
Mack, Nealon
MacLeod, Kenneth J.
Maeda, Kohichi
Maitland, David S.
Marriott, Joe E.
Marrocco, James A.
Marshall, Howard D.
Masters, Lewis W.
Matthews, Ian
McDermid, John E.
Mclntire, Richard E.
McKinney, H. Webber
Mellor, Douglas J.
Merrick, Edwin B.
Merrill, Howard L.
Millard, Joe K.
Mingle, P. Thomas
Misson, William
Moll, John
Morrill, Justin S., Jr.
Morris, Donald E.
Oct.
1976
Sept.
1975
July
1975
Sept.
1974
Oct.
1974
Aug.
1976
Apr.
1975
Feb.
1976
June
1974
Mar.
1974
Feb.
1975
Jan.
1975
Mar.
1977
July
1977
Mar.
1975
Feb.
1977
Aug.
1975
June
1975
Aug.
1974
July
1975
May
1974/
June
1977
Mar.
1976
Mar.
1975
Mar.
1974
Nov.
1976
Sept.
1974
Mortensen, A. Craig
Mueller, Louis F.
Munsey, Grant J.
Musch, Bernard E.
Muto, Arthur S.
N
Nov.
Feb.
Sept.
June
Mar.
July
Feb.
luly
Aug.
July
Oct.
Apr.
1973/
1977
1974
1975
1977
1975
1974
1976
1974
1977
1973
1974
1975
1977
Dec.
1974
Nov.
1973/
Apr.
1975
Mar.
1974
June
1976
Feb.
1977
Nov.
1974
Oct.
1973
July
1974
Nov.
1975
Feb.
1977
July
1974
Apr.
1975
Aug.
1974
Oct.
1976
Dec.
1973
Dec.
1975
Apr.
1975
Mar.
1975
Mar.
1977
Aug.
1975/
Dec.
1976
June
1976
Nadig, Hans-Jiirg
Neff, Randall B.
Nordman, Robert G.
O'Buch, Warren J.
Offermann, Robert W.
Olson, William E.
Osada, Kunihisa
Osterdock, Terry N.
P
Pannach, Arndt
Paulson, Gary R.
Pearson, Robert
Pecchio, Santo
Peck, Robert D.
Perdriau, Robert H.
Pering, Richard D.
Peterson, Kenneth W.
Pierce, Robert B.
Poole, John S.
Pope, Richard
Pratt, Ronald E.
Priebe, Durward
Q
Quenelle, Robert C.
Rauskolb, Roger F.
Ricci, David W.
Richards, Alan J.
Riebesell, Giinter
Riedel, Ronald J.
Riggins, Cleaborn C.
Risley, William B.
Robertson, James
Roos, Mark
Roy, Jean-Claude
Rude, Andre F.
Ruchsay, Walter
Rytand, William A.
Salfeld, Peter
Salesky, Emery
Saponas, Thomas A.
Sasaki, Gary D.
Schrenker, Helge
Schultz, James T.
Schultz, Steven E.
Scott, Peter M.
Seavey, Gary A.
Shar, Leonard E.
Sharritt, David D.
Small, Charles T.
Smith, Jeffrey H.
Smith, Richard L.
June
1976
Smith, Robert B.
Sept.
1973
Snow, David L.
July
1977
Snyder, David C.
Nov.
1976
Sommer, Heinz
June
1974
Sorden, James L.
Stallard, Scott J.
Stancliff, Roger
Jan.
1975/
Stedman, John M.
May
1977
Stefanski, Andrew
Nov.
1975
Stickel, Herbert P.
May
1976
Stickle, Ronald L.
Stinson, John
Stockwell, R. Kent
July
1974
Stone, Peter S.
Oct.
1975
Suehiro, Jun-ichi
Feb.
1976
T
Feb.
1975
Sept.
1973
Tabbutt, Richard D.
Taggart, Robert B.
Aug.
1975
Tamamura, Toshio
June
1976
Tang, Edward
Mar.
1976
Tillman, Lynn
July
1974
Trimble, Charles R.
Dec.
1973
May
Aug.
May
1975
1974
Toschi, Elio A.
Tung, Chung C.
1974
Tverdoch, Richard
June
1975
u
Apr.
1976
Oct.
1976
Uebbing, John T.
Oct.
1975/
Urquhart, J. Reid
June
1977
Dec.
1976
V
Van Bree, Kenneth A.
Dec.
1976
Van Brunt, Richard C.
Van Dyke, Eric J.
Veteran, David R.
May
1975
Vifian, Hugo
Jan.
1975
Vyduna, James B.
May
1976
w
Aug.
1977
Mar.
1975
Wade, John M.
Oct.
1974/
Wagner, William E.
Mar.
1977
Waitman, Thomas F.
Dec.
1974
Walker, Hugh P.
Nov.
1973
Walker, William T.
July
1976
Wang, Patrick H.
June
1975
Ward, Michael J.
Feb.
1976
Warp, Rick A.
Jan.
1977
Warren, Richard E.
Mar.
1977
Watanabe, Tak
Weber, Lynn
Weibel, Gerald E.
Jan.
June
Aug.
Jan.
1977
Whicker, Richard
1977
Wickliff, Robert G.
1975/
Winninghoff, Paul G.
1977
Witkin, Louis A.
Jan.
1975
Wolpert, David L.
Oct.
1975
Woodhull, Frederick
Jan.
1976
X
June
1974/
Jan.
1975/
Y
Oct.
1975
Mar.
1976
Yansouni, Cyril J.
Mar.
1976
Young, Ivan R.
Dec.
1974/
Aug.
1976
z
July
1976
Aug.
1975
Zamborelli, Thomas J.
Jan.
1977
Zellmer, Joel
May
1976
Feb.
1976
Mar.
1977
Feb.
1975
Jan.
1977
June
1974
Mar.
1977
Mar.
1975
Oct.
1974
Dec.
1974
Aug.
1977
Feb.
1976
Nov.
1973
May
1974
Jan.
1975
Feb.
1975
Dec.
1975
May
1974/
Nov.
1976
Sept.
1976
June
1975
Nov.
1975
Jan.
1975/
Oct.
1975
Aug.
1976
May
1974
Feb.
1974
Apr.
1977
Jan.
1976/
Oct.
1976
July
1977
Oct.
1974
July
1977
May
1974
July
1976
Feb. 1977
Feb.
1975
Aug.
1975
June
1975
Jan.
1976
June
1977
Nov.
1976
Feb.
1976
Dec.
1973
Apr.
1976
Aug.
1976
Aug.
1977
Sept.
1973
Nov.
1975
Sept.
1976
Aug.
1974
May
1976
Jan.
1975
July
1976
Mar. 1975
Nov. 1973/
Mar. 1976
Sept. 1974
Aug. 1977/
Sept. 1974
ASCII
Line
Counter
>— ► V 4*V
► az
► eom
► if
>-CR
► x 9 -x 4
► Y 9^V 5
Fig. 2. Character generator produces horizontal and vertical
bit patterns for alphanumeric characters and sends them to
the stroke generator.
m Load new ROM address into RAR from ROM
output
■ Increment RAR to next ROM address
■ Load new ASCII code into RAR and increment
character counter.
These control situations allow the ASM to step con-
secutively from one bit pattern to the next for por-
tions of a character that are unique, or to jump any-
where within the ROM to access portions of another
character that are common to the one being con-
structed. For example, an eight may be made from a
three and a pattern unique to an eight:
> + 3 = 8
This yields maximum efficiency in the use of ROM
and makes it possible to store a complete ASCII
character set plus a few Greek and lower-case letters
for engineering notation in 512 16-bit words of ROM.
Stroke Generator
To display high-quality lines with uniform inten-
sity, three signals have to be generated: the horizontal
component, the vertical component, and the blanking
signal. This is the job of the stroke generator.
The stroke generator converts digital bit patterns
into uniform line segments. The horizontal and ver-
tical lines are voltage ramps. The blanking signal is
generated from the horizontal and vertical com-
ponents and determines the line's intensity and turns
the beam on or off.
To generate a uniform straight line with constant
intensity, the signal moving the beam should be a
linear ramp, as shown in Fig. 3. A simplified dia-
gram of the circuit used to generate this signal is
Fig. 3. Lines are drawn by moving the beam with a smooth
ramp to maintain constant intensity.
shown in Fig. 4. A digital-to-analog converter (DAC)
generates the desired output level. The present out-
put value is subtracted from the DAC value to gen-
erate a difference AX, which is sampled and held.
Then the integrator switch closes and the sample-
and-hold switch opens, and the output ramps to the
desired output value.
For a given CRT drive, a certain number of elec-
trons per second are generated by the electron gun. If
the beam is moved twice as far in the same amount of
time, the electron density is halved, so the line is dim-
mer. It is a simple matter to generate an intensity level
that will compensate for this, knowing the horizontal
and vertical line lengths AX and AY:
Intensity = AV (AX) 2 + (AY) 2 ,
where A is a proportionality constant related to the
integration time.
In the 5420A, this is approximated using one-half
the sum of the magnitudes of AX and AY. This re-
sults in a slightly greater intensity for horizontal and
vertical lines than for diagonal lines of the same
length. However, this is of little consequence, because
the compensation is applied only for lines longer than
a certain threshold value. In other words, some
variation in intensity is permitted, although much
less than there would be without compensation. This
is because a slightly greater intensity for short lines
than for long lines not only livens the display, but
■ *c
H
5
Fig. 4. Simplified ramp generator circuit. A digital-to-analog
converter generates the desired value of the output. This is
subtracted from the present value and the difference is sam-
pled and held. Then the integrator switch closes and the
sample-and-hold switch opens, and the output ramps to the
desired value.
15
also introduces some information on how quickly
a plot is changing.
Mini-Cartridge Data Storage
The mini-cartridge has proved its utility as a data
storage medium in HP terminals and desktop com-
puters. 1,2 In the 5420A Digital Signal Analyzer, the
minicartridge is used for data storage and as a backup
store for a large semiconductor RAM memory.
The minicartridge holds about 250,000 16-bit
words of information, accessible at a 1-kHz word rate.
It was designed jointly by HP and 3M corporation as a
small, reliable storage device that could stand up to
the vigorous demands of a computer controlled sys-
tem. 3 A feature of the minicartridge is its belt drive,
which eliminates tape-to-capstan contact and en-
hances reliability.
There are two cartridge drives in the 5420A Digital
Signal Analyzer. The front-panel cartridge pro-
vides the ability to store and restore instrument set-
ups and data waveforms for later use. The second
cartridge drive is hidden under the instrument's top
cover. Its function is to back up 48K words of high-
speed volatile memory.
Memory Back-Up
The "personality" of the 5420A is stored in 48K
words of high-speed semiconductor RAM memory.
This memory is volatile, so it must be loaded during
the power-up sequence. The memory loading process
is accomplished in several steps and involves the
21MX K-Series Computer, a small bootstrap program
residing in ROM (non-volatile), ROM-stored micro-
MIOB
Tape Cartridge
Multiplex
Fig. 5. Two tape drives in the 5420A share read/write elec-
tronics and communicate with the central processor over the
MIOB. One drive is used for storing data and instrument
setups. The second drive is internal, and is used to back up the
5420 As semiconductor memory.
code, the module I/O bus (MIOB), and the hidden
cartridge.
When the power is switched on, the computer per-
forms an initial bootload opcode (ibl), which loads a
small bootstrap program from ROM into the com-
puter's main 48K memory. This program checks the
memory and tests the integrity of the MIOB, and then
proceeds to load data stored on the hidden cartridge,
filling the computer's memory. To enhance reliabil-
ity, the 48K memory contents are stored in IK rec-
ords, and there are multiple copies of each record on
the cartridge. If an error is encountered during the
loading of a record, alternate copies of the record are
used. If the alternate copies also have errors, the noise
reject threshold used in decoding the tape head signal
is changed. Thus the loading process is desensitized
Walter M. Edgerley, Jr.
With HP since 1 971 , Walt Edgerley
has designed power and hybrid
microwave amplifiers and, more
recently, the 5441 A Display Mod-
ule for the 5420A. He received his
BSEE degree from the University
of California at Berkeley in 1972 A
former professional bowler, Walt
participates in a variety of sports
and coaches young peoples'
baseball and basketball teams. He
was born in Albany, California, has
two sons, and now lives in Fre-
mont, California.
.
David C. Snyder
Dave Snyder designed the tape
cartridge hardware and the mod-
ule I/O bus for the 5420A. With HP
since 1971, he's been project
leader for the 5451 B Fourier
Analyzer and has done software
design for nuclear analyzers and
automatic test systems. Dave
Graduated from the University of
California at Berkeley with a BS
degree in engineering physics in
1965. Before joining HP he worked
as an astrodynamicist, a software
analyst, and a software designer.
He's done graduate work at three
universities in a variety of fields including computer science,
systems, and digital design. A native of Mankato, Minnesota,
Dave is married to a nurse, has three children, and lives in the
Santa Cruz mountains of California. His interests include mi-
croprocessing, games, cryptography, hiking, woodworking,
photography, and guitar.
16
to tape errors, and in fact, will load perfectly even in
the presence of multiple hard errors.
Cartridge Hardware
The cartridge hardware interfaces two tape trans-
port assemblies, each consisting of motor, head, and
preamplifier, to the 5420A module I/O bus (MIOB), as
shown in Fig. 5. The MIOB transactions involve send-
ing and receiving data, receiving commands (e.g.,
$RUN, $STOP, $read,.„), and sending status infor-
mation (e.g., %MOvrNG, %EOF,...) called "code words".
The motor servo's job is to maintain the tape speed
at 22 or 88 inches per second (ips), both forward and
reverse. The tape velocity increases linearly from a
stop to 22 ips in approximately 20 milliseconds; this
corresponds to accelerating the motor uniformly from
to 1300 r/min within one-half of one motor revolu-
tion or about 0.5 inch of tape travel. An optical tach-
ometer providing 2000 pulses per revolution is the
control feedback element.
Data is written on the tape bit-serially, encoded in
HP's delta distance format. 2 This is an efficient tech-
nique in which the recording density varies between
900 and 1600 bits per inch depending on the bit com-
position of the data. In this format, zeros are repre-
sented by short magnets (about 600 fjuin) and ones
are represented by long magnets (about 1000 /uin).
The control portion of the cartridge hardware han-
dles all MIOB transactions, performs serial-to-parallel
conversions, and handles exceptions (for example,
sending status code words to the computer whenever
an error is detected). The control section is implement-
ed as a PROM-driven 32-state algorithmic state ma-
chine (ASM).
A diagnostic mode is provided that allows software
read and write arbitrary patterns on the tape, instead
of being limited to reading and writing one and zeros.
Using the standard XIO pseudo-DMA opcode, the
signal at the tape head may be set or sensed with a
resolution of about one microsecond, equivalent to a
tape motion of about 20 /juin. This capability can be
used to read and record worst-case test patterns such
as frequency response patterns, dropout patterns, and
so on, for diagnostic purposes. E
References
1. R.G. Nordman, R.L. Smith, and L.A. Witkin, "New CRT
Terminal Has Magnetic Tape Storage for Expanded Ca-
pability," Hewlett-Packard Journal, May 1976.
2. D.E. Morris, C.J. Christopher, G.W. Chance, and D.B.
Barney, "Third-Generation Programmable Calculator Has
Computer-Like Capabilities," Hewlett-Packard Journal,
June 1976.
3. A.J. Richards, "Mini Data Cartridge: A Convincing Al-
ternative for Low-Cost, Removable Storage," Hewlett-
Packard Journal, May 1976.
Digital Signal Analyzer Applications
Analyses of two actual systems, one electrical and one
mechanical, show what the analyzer can do.
by Terry L. Donahue and Joseph P. Oliverio
THE 5420A DIGITAL SIGNAL ANALYZER is
basically a two-channel digital low-frequency
spectrum and transfer function analyzer. A major
application area is the analysis of mechanical struc-
tures, since these typically exhibit low-frequency
(below 25 kHz) oscillations. However, its versatility,
wide choice of measurements, and post-measure-
ment processing capability make it a useful tool in
other areas, such as acoustics, underwater sound,
control system analysis, phase noise analysis, and
filter design. This article describes two applications,
one electrical, the other mechanical. The examples
include the results of actual measurements made on
an electronic speed controller and a mechanical
structure.
Electronic Speed Controller
Fig. 1 is a block diagram of the speed controller for
the 5420A's own cartridge tape drive, which is driven
by an armature-controlled permanent-magnet dc
motor. An analog tachometer voltage is obtained by
filtering the output of an optical pulse tachometer.
The set point input R(jw) represents a command for
the motor to run at a constant speed. The feedback is
the analog tachometer voltage, which is proportional
to motor speed and therefore tape speed. System
noise, represented by S(jw), is contributed by several
elements including the unregulated dc motor voltage,
mechanical imbalances in the system, and varying
frictional forces.
The solid black summing node in Fig. 1 is added
to the system to introduce noise N(ja>) from the
5420A's random noise source. The measurement
technique is to measure the transfer function
T(jw)=X(jw)/N(jw) and compute the open-loop trans-
fer function G(jw)H(jw). This is possible because
17
R(i")
H
N(M
S(jo.)
G(j«.)
X(ja>) Y(jo>)
ll dc
j Motor
\c(ja>)
H(io))
Low-Pass
Filter
rt—
\
Tachometer
2000 Pulses/Rev
T(ja>)«G(jco)H(ja))/[l+G(ja;)H(j w )].
The black summing node in Fig. 1 must be added to
the system with some care. To provide isolation from
the noise source and to prevent disturbing the normal
operation of the system, an operational amplifier cir-
cuit, as shown in Fig. 2 , can be used. The Rs should be
matched to provide a gain | Y(jw)/X(jco) | = 1 to an accu-
racy consistent with normal parameter variations in
the system. The circuit should have unity gain and no
phase shift over the control system bandwidth.
Fig. 2. An operational amplifier circuit for introducing noise
N(ju>) into a system without disturbing the system.
Fig. 3 shows log magnitude and phase versus fre-
quency of the measured transfer function T(j to) . To get
the open-loop transfer function G(ja>)H(jaj) the
5420A's arithmetic operations are used to get the re-
sults illustrated in Fig. 4. From the figures, it is possi-
ble to estimate that G(jto)H(ja>) contains a pole at Hz
Fig. 1. Block diagram of a car-
tridge tape drive system to be
analyzed by the 5420A Digital
Signal Analyzer. The black sum-
ming node has been added to the
system to introduce noise N(joi)
from the 5420 A's random noise
source. The technique is to mea-
sure T(jw) = X(jm)IN(jo>) and com-
pute the open-loop transfer func-
tion G(j(o)H(jio).
and another at about 200 Hz. An analysis of the sys-
tem predicted a response dominated by the loop filter
and the motor. The loop filter was expected to contri-
bute a pole at Hz and a low-frequency zero, and the
motor a low and a high-frequency pole. The measured
result shows the pole at Hz, the high-frequency
motor pole near 200 Hz, and the low-frequency filter
zero nearly perfectly cancelling the low-frequency
motor pole.
Stability Analysis
Once G(j&j)H(ja;) has been obtained, it is possible to
determine the absolute and relative stability of the
system. A simplified version of the Nyquist stability
criterion that can usually be applied to real systems
states that a system with an open-loop transfer func-
tion G(jo))H(jw] that has no poles in the right half of the
complex plane is closed-loop stable if the Nyquist
plot (imaginary part versus real part) of G(jw)H(jw) for
0< to < 50 does not enclose the critical point -1+jO.
Fig. 5a shows the results of using the coordinate
keys to display the measured G(jto)H(ja>) in the
Nyquist format. The system is seen to be absolutely
stable since the critical point is not enclosed. Relative
stability is measured by how close G(jw)H(jw) comes
to enclosing the critical point. This is traditionally
measured by the gain and phase margins, which are
easily determined by again changing coordinates. In
Fig. 5b G(jw)H(jw) is displayed using coordinates of
log magnitude versus phase. The gain margin is 23 dB
and the phase margin is 75 degrees.
Fig. 3. Closed-loop transfer func-
tion T(j<o) measured by the 5420 A.
18
Fig. 4. The result of calculating
G(ju,)H(jo>) = T(jm)/[1 -T(M]
using the 5420 As arithmetic keys.
The measurements were repeated on the system
with an extra gain block inserted into the loop. The
Nyquist display is shown in Fig. 6a superimposed on
the original Nyquist display. The original system is
conditionally stable. Adding gain, while not making
it unstable, has decreased the relative stability. From
Fig. 6b, it can be seen that the gain margin has de-
function is then just T(jco), which is shown in Fig. 3.
Characterizing Structural Vibrations
One way of modeling the dynamic characteristics
of a mechanical structure is to identify its modes of
vibration. An automobile, for example, may ride
smoothly at 40 mi/hr, vibrate considerably at 50 mi/hr,
Fig. 5. (a) Nyquist display of
open-loop gain G(ja>)H(ja>). (b)
Same function in different coordi-
nate system permits measurement
of gain margin (gain at -180°
phase) and phase margin (phase
difference from -180° at dB
gain).
creased to 15 dB and the phase margin to 45 degrees.
The only question remaining is the shape of the
closed-loop transfer function. In the general case, this
is given by G(jw)/[l+G(jw)H(jw)]. If the output of the
speed controller is defined to be the tach voltage, a
known function of the tape speed, the system is
unity-feedback, with H(jw) = l. The closed-loop transfer
and then ride smoothly again at 60 mi/hr. This hap-
pens because one of the modes of vibration of the car,
perhaps in the front suspension, body, or frame, is
excited at 50 mi/hr but not at the other speeds. A mode
is defined by a natural frequency of vibration, a damp-
ing value that defines how quickly the vibration will
decay to zero when external forces are removed, and a
Fig. 6. The measurements of Fig.
5 repeated with more gain in the
system. Gain and phase margins
have decreased.
19
2
3 J. 1
4
>^ \ 20
5 ^-<
19^>4
6 ^?
18 )(\/
7
17 j/ /(s'
8
• 16
*^dfi
15^-K/
y ^*s
14^K/"^
KTti
13
^0\J 2
Accelerometer ^
»X
►
k To 5420A
Ch. 2
Mr
►
Charge
k To 5420A
Ch. 1
..iV-^iCf
Amplifiers
,"''* ' ■:■■■
Shaker
Power Amplifier
i«L - ,'
^
From R450A
^
Noise Generator
Fig. 7. /A stee/ p/ate is to be analyzed by the 5420A. An
electrodynamic shaker supplies the stimulus. The plate's re-
sponse is detected by accelerometers at various points on the
surface.
mode shape, or spatial distribution of the amplitude
and phase of the resonant condition over the struc-
ture.
In mechanical design, one objective is to design a
structure whose modes of vibration occur at frequen-
cies outside the frequency range of known external
driving forces. When this is not possible, it may be
X : 55 1 . 6 1 Y:20.223
TRANS I »A: 20
30.000
LGMflO .
K I
I
-30.000
fijNt
Tf
PERK;
• Fr" Z 55I.048 ID: 559.59
880. e
9
Fig. 8. A result of the measurement of Fig. 7 for one point on
the plate surface. The resonance at 551 Hz (identified by the X
cursor) represents a mode of vibration with a damping factor
of 0.559%.
possible to add damping material to the structure,
which has the effect of damping its modes of vibration
as well as reducing its amplitude of vibration at any
frequency.
Modal parameters — frequency, damping, and
mode shape — can be identified from transfer function
measurements on a structure. The following example
illustrates how the 5420A can be used to identify the
modes of vibration of a flat plate.
Modal Survey
The setup is shown in Fig. 7. The 5420A's noise
generator is used to excite the structure by means of
an electrodynamic shaker. A force transducer
mounted between the structure and the shaker pro-
vides the input signal for channel 1 of the analyzer.
The accelerometer mounted on the surface of the steel
plate provides the response signal for channel 2 of the
analyzer. The 5420A measures the transfer function
of the structure between the stimulus and response
points. The result is shown in Fig. 8 for position #1 on
the surface. Each peak represents a mode of vibration
of the structure. The resonant frequency (FR) and per-
cent critical damping (%D) of each mode can be deter-
mined by placing the X cursor on the peak and pres-
sing the PEAK key.
Measure a Set of
Transfer Functions.
Store on Cartridge.
Use Cursor to Read
Quadrature Values
at Resonant Frequencies
3) Plot Values.
A1
B1
C1
D1
f, f,
A2 B2 C2 D2
Fig. 9. How modal analysis is done with the 5420A Digital
Signal Analyzer.
20
Fig. 10. Results of a modal analysis of the steel plate.
Each response point on the structure will exhibit a
different transfer function with respect to the input.
For lightly damped structures the amplitude of the
mode can be determined from the imaginary, or quad-
rature, part of the transfer function. Thus the mode
shape can be drawn by recording the imaginary value
of the transfer function at each measurement point for
the resonance of interest and plotting these values as a
function of their position on the surface. The process
is shown pictorially in Fig. 9. The result of recording
each imaginary value and plotting it as a function of
its position on the surface is shown in Fig. 10.
Reducing Unwanted Vibrations
The two most common methods of reducing un-
TRANS 1
TRANS 1
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R»: 47
Hi
f
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»A: 20
800.0
UUJ
30.000
30.000
LGMflG
DB
h
Uv
/
1 i
LGMAG
- DB
v<f
-30.000
30 000
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EXPAND:
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800.00
Fig. 11. Measurements before and after adding mass to the
steel plate. Extra mass decreases the amplitudes and fre-
quencies of the resonances.
wanted vibrations are to add mass to the structure and
to increase its stiffness. Both will affect the frequency
of a resonance. Adding mass will lower a natural
resonant frequency. Increasing the stiffness will in-
crease a natural resonant frequency. An example of
the result of adding mass to the steel plate is shown in
Fig. 11. Not only are the resonances lower in fre-
quency but their amplitudes have decreased because
the added mass increased the damping of the struc-
ture. E
Joseph P. Oliverio
Joe Oliverio received his BSEE
degree in 1968 from the University
of Santa Ciara. After a year as a
design engineer, he joined HP in
1969 as a sales engineer. Now a
digital signal analyzer product
marketing engineer, he's written
two magazine articles on digital
signal analysis. Joe was born in
San Jose, California and still lives
there. He's married and has two
children. He's an amateur magi-
cian and an actor in local theater
productions, and he enjoys skiing,
tennis, and golf.
Terry L. Donahue
Terry Donahue earned his BSEE
and MSEE degrees at the Uni-
versity of Southern California in
1971 and 1972, and joined HP in
1972 as a design engineer. For
the 5420A, he wrote the display
software and compiled an appli-
cation note on control system
measurements. In 1976, he re-
ceived his MBA degree from the
University of Santa Clara. He's a
member of IEEE. Terry comes
from Long Beach, California.
He's married and now lives in
Santa Clara.
21
Printing Financial Calculator Sets New
Standards for Accuracy and Capability
This briefcase-portable calculator has several new functions
and is exceptionally easy to use. Most important, the user
need not be concerned about questions of accuracy or
operating limits.
by Roy E. Martin
HEWLETT-PACKARD INTRODUCED its first
financial calculator, the HP-80, in 1973. 1 The
HP-80 was followed, although never replaced, by the
HP-81, the HP-70, the HP-22, 2 and the HP-27.
The new HP-92 Financial Calculator, Fig. 1, while
superficially similar in many respects to these units,
vastly exceeds all of them in functional capability
and accuracy. Originally conceived as a briefcase-
portable printing calculator packaged like the HP-91 3
and the HP-97 4 and having the financial capabilities
of the HP-22, the HP-92 in reality goes far beyond this
modest goal. Among its features are:
■ Compound interest keys redefined to enhance
capability and ease of use
■ A printed amortization schedule, correctly rounded
and clearly labeled
■ Internal rate of return (IRR) that allows the user to
enter up to 31 cash flows with arbitrary positive
and negative values
■ The greatest accuracy ever achieved in any HP
financial calculator
■ Calendar functions with a range of 900,000 days
(approximately 2464 years)
■ Bond and note functions that conform to Securities
Industry Association equations 5
■ Three types of depreciation that can be done
after entering data only once
■ Means, standard deviations, and linear regression
for two variables.
New Compound Interest Keys
The cornerstone of the HP-80 and all subsequent
HP financial calculators is the row of compound in-
terest keys: n i PV PMT FV
n = number of compounding periods
i = percent interest per period
PV, PMT, FV specify the cash values in various
problems (PV = present value; PMT = payment;
FV = future or final value).
These keys allow the user to solve for an unknown
value by first placing known values in the calculator
and then pressing the key corresponding to the
unknown.
Example: Find the monthly payment due on a
36-month, 12%, $3000 loan.
Keystrokes
These keystrokes 36 n
place the known 1 i (12% annual is 1% per month)
values into the 3000 PV
calculator
Then press:
Answer displayed:
PMT
99.64 Monthly Payment
This sequence of keystrokes will solve this problem
on all previous HP financial calculators.*
The compound interest keys solve three types of
problems, based on the following three equations. (In
these and subsequent equations, i is a decimal frac-
tion, e.g., 0.05 for five percent.)
FV = PV(l+i) n
PV = PMT[l-(l + ir n ]/i
FV = PMT[(l+i) n -l]/i
Compound Amount
Loan
Sinking Fund
Each of these equations has four variables. As long
as three of the four variables are known (n or i must
be one of the three knowns) a user can solve for an
unknown.
Because there are three distinct equations and only
one set of keys, it is necessary to specify which equa-
tion is involved. This is done automatically through
the use of status bits (flags). Internally, status bits are
set when values associated with n, i, PV, PMT, FV are
keyed into the calculator. As soon as three status bits
are set, the equation is specified and a value can be
computed.
On the HP-80, known values are pushed onto the
stack and then lost when a value is computed, requir-
ing the reentry of data on every new computation.
The HP-70, HP-22, and HP-27 have separate registers
to hold the financial values but require special func-
tions to clear the status bits.
*The HP-27 requires the use of a shift key but is fundamentally the same.
22
This design, although creatively conceived and
cleanly implemented, is inconvenient for chained
calculations. Also, an important class of problems,
loans with a balance, cannot be solved without tedious
iteration by the user.
The same keys, n, i, PV, PMT, FV, were to be on the
HP-92. However, we wanted to improve and simplify
their use. The most attractive alternative came in the
form of a more general equation:
PV (l+i) n + PMT [(l + i) n -l]/i + FV = 0.
The three equations in previous calculators are all
special cases of this one, up to a sign change. The
basic premise in this equation and a major difference
between the HP-92 and other financial calculators
is that money paid out is considered negative and
money received is considered positive.
Implemented in the HP-92, this equation allows
free-format problem solving, letting the user change
any variable at any time or solve for any value at any
time. It also increases the functional capability of the
calculator to include loans with a balance, fixes the
roles of PV, PMT, and FV, making them easier to ex-
plain, reduces the number of equations from three to
one, and eliminates the need for status bits — the data
in the calculator determines the problem to be solved.
In the early stages of the project, the new com-
pound interest equation was simulated. The increase
in capability and simplicity was substantial. Within
minutes, inexperienced people could understand the
Fig. 1. HP-92 Investor is a finan-
cial printing calculator with supe-
rior accuracy and capability. Key-
board is designed to prompt the
user, making many problem solu-
tions obvious even without a
manual.
concept and apply the keys to problems formerly con-
sidered too complicated to solve. Naturally, we were
pleased. The new calculator would be more capable
than earlier designs and easier to use as well. But our
satisfaction was short-lived, for it turned out that here,
Fig. 2. Newton's method is used by the HP-92 to solve com-
pound interest problems. Starting from some point i on the
graph of an eguation, the goal is to find the root of the equation,
or the point where the graph crosses the axis. Drawing a
tangent line to the graph at i and finding where this line
crosses the axis gives a second point /,. This process is
repeated to find i 2 , '3, and so on, until a point is reached that is
close enough to where f=0. i is called the initial guess.
23
Sinking Fund
1 1 1 1 1
(i)
rffl
/-Root
1 1 1 1 1
-5 -4 -3 -2 -1
i(%)
f\ I I I
0/1 2 3 4
Fig. 3. Equations used in previous HP financial calculators
have favorable graph shapes (the one shown is typical), so
that starting from any initial guess i the steps taken by
Newton's method are always toward the root.
as usual, nothing is free.
The numerical analysis used in solving the three
equations in the HP-80 had been formidable. Yet the
accuracy and reliability of the algorithms was border-
line and their performance deteriorated unaccept-
ably when they were applied to the new more gen-
eral equation. The most difficult problem was solving
for i in the compound interest problems. Internally,
this involves the microprogrammed application of
Newton's method in the solution of polynomial equa-
tions (see Fig. 2).
Newton's method requires an initial guess, i ,
at the root of f(i) = 0. Subsequent values are produced
using
until
ik+il < required error limit. Basically, we
slide down the graph of f(i) sawtoothing into the
solution.
Three factors that affect the use of Newton's method
are the shape of the graph, the accuracy of evaluation
of the function f(i] and its derivative, and the quality
of the initial guess . For certain graphs any reasonable
initial guess will produce convergence to the correct
answer. This was the case with the equations solved
by previous HP financial calculators (see Fig. 3).
Inaccuracy in evaluation of the function and its
derivative can cause various problems. For example,
a small error can cause the iteration to step in the
wrong direction, say to the previous point, resulting
in an infinite loop. Worse yet, it can produce a wrong
answer. The new more general equation was more
sensitive than the old to round-off errors, and intro-
duced another difficulty not encountered before.
The quality of the initial guess became a critical
issue. Unless the initial guess was good enough, New-
ton's method would fail (see Fig. 4). With this in
mind, we implemented several transformations to
change the shapes of the graphs in an attempt to make
Newton's iteration less sensitive to poor first guesses.
We also carried extra digits and programmed numeri-
cally stable formulas to diminish the impact of round-
ing errors on the accuracy of intermediate calcula-
tions.
But our work was far from done. Even with the
transformations and increased accuracy, initial gues-
ses in error by less than 1% proved inadequate, be-
cause convergence was too slow when n was large.
After four months of careful examination and simu-
1 1 1 1 1 1 1 1 1 1
(i)
I I I
1 1 1 1 1 1 1 1 1 1
-10 -9 -8 -7 -6 -5 -4 -3 -2 -1
i(%)
I I I
1 2 3
Fig. 4. Modified equation used in HP-92 enhances ease of
use, but is more difficult to solve. Shape of graph is such that
some initial guesses will cause Newton's method to step away
from the root. To prevent this a strategy was developed that
produces initial guesses accurate to five decimal places.
24
Using the n, i, pv, pmt, fv Keys
Corresponding to each of these keys is a storage register. To put a value
in the storage register, just key in the value and then press the approp-
riate key. Money paid out is represented as negative and money re-
ceived is represented as positive.
Problem:
1. If you deposit $10,000 in a fund that pays 7.75% annual rate, how
much could you withdraw 12 years later?
2. If, in addition, you deposit $1000 each year thereafter, how much
would you be able to withdraw after 12 years?
3. If you wanted to withdraw $45,000 at the end of the 1 2-year period,
how much would you have to deposit each year?.
4. If you could deposit $18,500 initially, how much would you have to
deposit each year to be able to withdraw $45,000 at the end of the 1 2
years?
Solution:
Press cl fin . This clears the registers.
1. Key In Then Press Comment
12 n This is the number of years.
7.75 This is the periodic interest rate.
10,000 chs pv You are putting the money into the bank so you
key it in as negative.
fv This tells the calculator that you wish to solve for
the cash flow at the end of the time period.
See displayed: 24.491. 05, the amount you could withdraw in 12 years.
2. After values are keyed in (or calculated), they remain in the registers.
To do the second pari of the problem, all we have to do is key -1000
into pmt (12 remains inn, 7.75 ini and -10,000 in pv) and then press fv
Key In Then Press Comment
1000 chs pmt Again payment is negative because you are
giving money to the bank.
fv This tells the calculator to find the cash flow at
the end of the 12 years.
See displayed 43, 169. i7,The amount you could withdraw after 12
years.
3. If you needed to withdraw $45,000 and wanted to find out what your
yearly deposit would be. put 45.000 into fv and then tell the calculator
to solve for pmt
Key In Then Press Comment
45,000 fv At the end of the 12 years you will receive
$45,000.
pmt This tells the calculator to find the annual de-
posit you must make.
See displayed -i096.85.The amount you must deposit annually.
4. Now put -18500 into pv, then press pmt
Key In Then Press Comment
18,500 chs pv You plan to deposit $18,500 at the beginning of
the 12 years.
pmt What will your deposit be so that you can still
withdraw $45,000 at the end of 12
years?
This tells you that you could withdraw this
amount each year and still get $45,000 at the
end of 12 years.
See displayed 16.50
Fig. 5. An example illustrating how natural the HP-92's com-
pound interest keys are to use. An important difference from
previous financial calculators is that money paid out is con-
sidered negative and money received is considered positive.
lation we devised an initial guess strategy that pro-
duces guesses correct to five places over all ranges of
PV, FV, PMT, and i, and with n as large as 10 8 . Com-
putation time for i was reduced to about a dozen
seconds.
Some of the techniques employed were:
■ An initial guess strategy that selects an initial guess
by problem classification, the production of as
many as three guesses, and the selection of the
final initial guess based upon the three guesses
■ Enhanced accuracy in +, — , x, -^, In, e x
■ Special evaluation of [(1 +i) n - l]/i to avoid damage
from cancellation
■ Carrying more digits internally than any previous
HP financial calculator.
In the final implementation of the n, i, PV, PMT, and
FV keys we were able to achieve reliable functional
capability over a wide range of data and problems, a
dramatic enhancement in ease of use, and definitive
accuracy (see accuracy discussion) exceeding that of
any previous HP calculator.
Fig. 5 demonstrates how easy the new compound
interest keys are to use.
Internal Rate of Return
Given an initial investment and a series of uneven
cash flows CF , CF lf ..., CF n occurring at equally
spaced time intervals the IRR (internal rate of return)
is the interest rate that satisfies the following equa-
tion:
CF + CF 1 (l+i)- 1 +CF 2 (l+ir 2 + ... + CF n (l+ir n =0 .
The only other HP financial calculators to produce
IRR are the HP-27, which allows eleven cash flows,
and the HP-81, which allows ten cash flows. The
HP-92 allows up to 31 uneven cash flows.
We again applied Newton's method to solve this
equation, but in this case the shape of the graph pre-
sented a different type of problem. In the compound
interest problem there is only one root (the graph
crosses the axis only once). In the IRR problem it is
possible for the equation to have many roots. Des-
cartes' rule of signs allows polynomial equations with
several changes of sign in their coefficients to have
several roots. Since the cash flows in the IRR problem
represent the coefficients of a polynomial (see equa-
tion), cash flows that change direction more than
once produce this possibility. However, if there is
more than one root, none of the solutions will be
financially meaningful. To avoid this complication,
the HP-2 7 will not allow more than one sign change.*
Example: Consider the following two problems.
Negative values represent investment and positive
values represent income.
Problem 1 Problem 2
-$10,000
$ 2,000
-$ 1,000
$13,000
The HP-27 produces an answer of 11.83% for Prob-
lem 1 but returns ERROR for Problem 2. To most users
it is not apparent why this happens.
We wanted to remove this kind of limitation. Again
'It should be noted here that the techniques used in the HP-27 were the best available at the time. Many
implementations of IRR take no precautions to protect the user from anomalous answers.
Initial
-$10,000
Year 1
-$ 1,000
Year 2
$ 2,000
Year 3
$13,000
25
after considerable investigation we were able to im-
plement an IRR function with a much broader range.
For Problem 2 above the HP-92 produces the correct
answer of 12.99%.
The IRR function on the HP-92 will produce the
correct answer for any problem with up to 31 cash
flows and any number of sign changes, provided that
there is at least one sign change and that there is only
one significant sign change. In general, this means
that there is only one real root. Multiple sign changes
are allowed provided that all but one of the cash flows
changing sign are small in comparison to the other
cash flows.
Example:
Problem 3
Problem 4
Acceptable
Unacceptable
Initial
-$100,000.00
-$100,000.00
Year 1
$500.00
$500,000.00
Year 2
-$200.00
-$200,000.00
Year 3
$100.00
$100,000.00
Year 4
$150,000.00
$150,000.00
For Problem 3 the HP-92 produces the correct
answer of 10.77%. For Problem 4 the HP-92 will cal-
culate indefinitely. The mathematically correct but
financially meaningless answers to Problem 4 are
-147.31% and 362.98%.This does not mean that the
problem is financially meaningless, but only that IRR
is not the way to attack it. If there is a financially
meaningful answer to an IRR problem the HP-92 will
find it.
Bonds
The SIA (Securities Industry Association) hand-
book 5 specifies certain procedures for the calculation
of bond values. Most bonds have semiannual coupon
periods determined by their maturity dates. For
example, if a bond matures on December 15, 1985,
then the coupon periods will end on June 15, 1985,
December 15, 1984, June 15, 1984, and so on. A bond
is not usually purchased on a coupon date (see Fig. 6).
This implies that both simple and compound interest
must be used during calculations of price and yield.
The SIA procedure for the calculation of purchase
price involves the exact number of days in the coupon
period in which the bond is purchased. The number
of days in a coupon period can vary from 180 to 184.
Inside the HP-92 the calendar functions determine
the exact number of days to the end of the coupon
period from the purchase or settlement date, automat-
ically taking leap years into account (Fig. 7). The
computations can be based on a 360 or 365-day year.
A Manual on the Keyboard
The HP-92 's keyboard is designed to prompt the
user and make it obvious how to solve many prob-
lems. Keys of the same kind are grouped together. In
6 Months
6 Months 6 Months
August 31, 1977
Possible Settlement Date
Maturity Date
6/15/77
12/15/77
12/15/84
6/15/85
12/15/85
Fig. 6. In bond calculations, coupon dates are determined
by the maturity date and are six months apart. Settlement (pur-
chase) date can be any business day. Built-in HP-92 cal-
endar functions determine the exact number of days between
the settlement date and the coupon date.
many problems all required input parameters have
individual storage registers. To place a value in one of
these registers the user simply keys in the value and
then presses the key corresponding to that register.
Example: There are three types of depreciation:
straight line (SL), sum of the years digits (SOYD), and
declining balance (DB). The input parameters and the
corresponding keys are life (LIFE), starting period (N1),
book value (BOOK), ending period (N2), salvage value
(SAL), and declining balance factor (FACT). These val-
ues are loaded into their registers using the blue and
gold shift keys where appropriate. Once this is done,
any or all of the three types of depreciation schedules
may be calculated by pressing the SL, SOYD, or DB
keys.
Accuracy and Operating Limits
Everyone who participated in the HP-92's design
wanted to produce a calculator whose reliability, ac-
curacy, and capability would exceed whatever might
reasonably be demanded of it. Previous calculators
would have to be surpassed, if only because as time
passes, users take previous accomplishments for
granted and demand more. One target for improve-
ment was accuracy. Consider the following slightly
unrealistic problem.
Example: Find the present value and the future
value of 63 periodic payments of one million dollars
each at the (very tiny but still positive) interest rate
i = 0.00000161%.
Problem:
Calculate the price of a corporate bond with
a settlement date of August 24, 1 977, a matur-
ity date of March 15, 2000, a coupon rate of
8.75% and a yield of 8%. (Calculated on
30-day month, 360 day year.)
Solution:
Enter the settlement date, maturity date,
coupon rate, and yield. Press price The
bond's accumulated interest and price are
then printed.
8.24197?
ST
3.152000
RT
8. 750000
CFH
S. 000000
YLD
B0HD $360
FRC
3.864583
hi
107.768456
***
Fig. 7. A bond problem and the HP-92 solution. That Febru-
ary has only 28 days is automatically taken into account.
26
HP-80 HP-22,27 HP-92
PV 62,608,695.65 63,000,000.00 62,999,967.54
FV 62,608,695.65 62,981,366.46 63,000,031.44
The HP-92 answers are correct, but more significant,
the other answers are clearly wrong: interest is pos-
itive but money is lost.
Obvious errors even on such unrealistic problems
can undermine user confidence. The only way
to prevent apprehension is to preclude all anomalies.
For this reason, we set out to produce such robust
algorithms that the user need never be concerned
with questions of accuracy or operating limits. The
extent of our success may be gauged by the reader's
readiness to forget the limitations explained below.
Calendar Functions: IS, ST, MT Dates of issue, set-
tlement, maturity
A DAYS Days between dates
DATE + DAYS
g PRINT x Day of the week.
These functions accept dates from October 15, 1582
to November 25, 4046. The first date marks the in-
ception of the Gregorian calendar, now in use through-
out Europe and the Americas, in which leap years are
those evenly divisible by 4, but not by 100 unless
also by 400. (The year 2000 will be a leap year, but
not 1900 nor 2100.) The second date is determined by
internal register limitations, not by any special know-
ledge of the future.
Mathematical Operations: +, -, x, +, 1/x, %, %S, A%,
Vx, e", LN
Error is less than one unit in the last (tenth) signif-
icant digit over a range of magnitudes including
10"" and 9.999999999X10". y x is also accurate to
within one unit in the last significant digit for 10~ 20
=£ y x =£ 10 20 ; outside that range the error is less than
ten units in the last significant digit.
Statistics: X+, 2-
These keys accumulate various sums using arith-
metic to ten significant digits. This determines the
range and accuracy achievable by the other statistical
keys y, LR, r, x, and s. For x data consisting of four-
digit integers, x and s will be correct to ten sig-
nificant digits and y, r, and LR will be in error by less
than the effect of perturbing each y value by one unit
in its tenth significant digit. For x data with more than
four digits per point the error can be significant
if the data points have redundant leading digits;
in this case both time (keystrokes) and accu-
racy will be conserved if the redundant digits are not
entered, following recommendations by D. W. Harms. 6
Bond Yield and Interest Rates: YIELD, I, IRR.
The error will be smaller than one unit in the last
(tenth) significant digit or 0.000000001 , provided that
the number of periods n does not exceed 1,000,000,
and for IRR, provided that the cash flows reverse sign
significantly only once as described above. These
rates are calculated far more accurately than the Sec-
urities Industry Association requires.
Money Values: PRICE, PMT, PV, FV, AMORT, SL,SOYD, DB, n
Errors will be smaller than the effect of changing all
input values in their tenth significant digits. Typi-
cally, this means that if (l + i) n does not exceed 1000
then errors will be less than one unit in the last (tenth)
digit. This amounts to a fraction of a cent in trans-
actions involving tens of millions of dollars.
Verifying Accuracy
A simple means of verifying the accuracy of a given
computation on any calculator is to attempt to
recalculate the known quantities using a quantity
the calculator has computed based on the knowns.
Example: Key the following values into the HP-92:
MAN E NORM Controls printing of keyboard operations.
i for calendar, bond/note, and i
COMPOUND INTEREST
n Stores or computi
■mber ot periods
12* Converts number of periods from years to months.
i Stores or computes interest rate per compounding period.
12- Converts interest from yearly to monthly rate.
PV Stores or computes present value (initial cash flow at the b
ginning ol a financial problem].
FV Stores or computes future value (final cash flow at the end of
financial problem].
PMT Stores or computes payment amount
DISCOUNTED CASH FLOW ANALYSIS
NPV Computes net present value of future cash flows.
IRR Computes
BONDS AND NOTES
e of n
i of s
; of up to 31 cash
PRICE
YIELD
IS, ST
CALL
CPN
DEPRECIATION
BOOK
LIFE
SAL
Stores or computes price of bond or note.
Stores or computes yield (percentage] of a bond or note.
Stores the issue and settlement dates of bond or note for
calculations.
Stores the maturity date of a bond or nole.
Stores the call price or redemption value of a bond or note
Stores the coupon amount (percentage) for bond or note
calculations.
Calculates straight-line depreciation schedule.
Calculates sum-of-the-years digits depreciation schedule.
Calculates declining balance depreciation schedule.
Stores book value of an asset.
Stores depreciable life of an asset
Stores salvage value of an asset.
Stores the starting year for a depreciation schedule.
Stores the ending year for a depreciation schedule.
FEATURES AND SPECIFICATIONS
HP-92 Investor
PERCENTAGE
CALENDAR
2000 Year
Calendar
DATE+DAYS
A DAYS
g PRINT x
STATISTICS
Computes percent.
Compules percent of change between two numbers.
Computes percent one number is of a total.
October 15, 1582 to November 25, 4046.
date from a given date and i
Computes a future c
fixed number of days.
Computes number of days between dates.
For a given date, prints its day of the week
Automatically accumulates two variables for statistics
problems: Ix, ly, lx 2 , ly 2 , Sxy, and number of terms n,
Deletes statistical variables for changing or correction.
Computes mean for x and y
Computes standard deviation for x. and y.
Linear regression of trend line.
Linear estimate.
Correlation coefficient.
Stores number in one of 30 storage registers . Performs storage
register arithmetic upon 10 of the registers.
Recalls number from one of 30 storage registers.
PRINTING AND CLEARING
AMORT Prints amortization schedule.
LIST: FINANCE Prints all values for compound interest problems, bonds
notes, and depreciation schedules.
PRINT x Prints contents of display.
LIST: STACK Prints contents of operational stack.
LIST: REG I Together print contents of 30 addressable storage regis'
CLx Clears display.
CL FIN Clears financial functions for new problem
CL REG CLV Together clear 30 addressable storage registers.
CLEAR Clears entire calculator— display, operational stack, all sto
registers, and financial functions.
NUMBER ENTRY AND MANIPULATION
ENTER!
CHS
x^y RI RT
EEX
RND
LASTx
MATHEMATICS
Separates numbers for arithmetic and other functions.
Changes sign of displayed number of exponent.
Functions to manipulate numbers rn operational stack.
Enter exponent of 10.
Rounds actual number in display to number seen in display.
Recalls number displayed before last operation back to
display.
Raisi
s number to power.
9 Natural antilogarithm.
LN Natural logarithm.
1/x Reciprocal.
+ - x + Arithmetic functions.
PHYSICAL SPECIFICATIONS
WIDTH: 22.9 centimetres (9.0 In).
LENGTH: 20.3 centimetres (B.O in).
HEIGHT: 6,35 centimetres (2.5 in).
WEIGHT: 1,13 kilograms (40 oz).
RECHARGER/AC ADAPTER WEIGHT: 170 grams (6 02).
SHIPPING WEIGHT: 2.7 kilograms (5 lb 15 oz].
TEMPERATURE SPECIFICATIONS
OPERATING TEMPERATURE RANGE: 0^ to 45 ; C (32*F to 1 13 = F): with papei
5% to 95% relative humidity.
CHARGING TEMPERATURE RANGE: 15= to 40°C (59° to 104°F).
STORAGE TEMPERATURE RANGE: -40 c to +55"C (-40° to +13TF).
POWER SPECIFICATIONS
AC: Depending on recharger/ac adapter chosen, 115 or 230V +10%, 50 ti
60 Hz.
BATTERY: 5.0 Vdc nickel-cadmium battery pack.
BATTERY OPERATING TIME: 3 to 7 hours.
BATTERY RECHARGING TIME: Calculator off. 7 to 10 hours: calculator or
17 hours,
PRICE IN U.S.A.: S625.
MANUFACTURING DIVISION: CORVALLIS DIVISION
1000 N.E. Circle Boulevard
Corvallis, Oregon 97330 U.S.A.
27
11=111.1111111, i = 2. 222222222, PV = 333. 3333333,
PMT=4. 444444444. These numbers are selected to
make any loss of digits noticeable, but are otherwise
arbitrary.
Now solve for FV. The HP-92 gives FV =
— 5931.82294. Now recalculate the known quantities.
The HP-92 answers are n = lll. 1111111, i =
2.222222222, PV = 333. 3333333, PMT=4. 444444443.
Note the loss of one digit in the last place of PMT.
Then resolve for FV. The HP-92 again gives FV =
-5931.82294, showing that the lost digit has no
impact.
Acknowledgments
The HP-92 represents the efforts and contributions
of many people drawing upon technical advances in
the mathematics of finance as well as in materials,
mechanics, and electronics.
The bulk of the development was done by Paul
Williams and me. The algorithms are based primarily
on work done by Professor W. Kahan of the University
of California at Berkeley. The product, as it is now
defined, would never have been implemented with-
out the early leadership and creative contributions of
Bernie Musch. The hard work and enthusiasm of the
following people contributed much to the total prod-
uct and they can take pride in their extensive con-
tributions: Jim Abrams (manual), Janet Cryer (appli-
cations book), A.J. Laymon, Dennis Harms, Hank
Suchorski, Bob Youden, Bill Crowley, and John van
Santen. I would also like to thank Bob Dudley for his
support and encouragement, ff
References
1. W.L. Crowley and F. Rode, "A Pocket-Sized Answer
Machine for Business and Finance," Hewlett-Packard Jour-
nal, May 1973.
2. R.B. Neff and L. Tillman, "Three New Pocket Cal-
culators: Smaller, Less Costly, More Powerful," Hewlett-
Packard Journal, November 1975.
3. B. E. Musch and R. B. Taggart, "Portable Scientific Cal-
culator has Built-in-Printer," Hewlett-Packard Journal,
November 1976.
4. P. D. Dickinson and W. E. Egbert, "A Pair of Program-
Compatible Personal Programmable Calculators,"
Hewlett-Packard Journal, November 1976.
5. B. M. Spence, J. Y. Graudenz, and J. J. Lynch, Jr., "Stan-
dard Securities Calculation Methods — Current Formulas
for Price and Yield Computations," Securities Industry As-
sociation, New York, 1973.
6. D. W. Harms, "The New Accuracy: Making 2 3 = 8,"
Hewlett-Packard Journal, November 1976.
Roy E. Martin
■ Roy Martin did product definition,
> microprogramming, and numeri-
cal analysis forthe HP-92. A native
Californian, he was born in San
Mateo, and received his BA de-
gree in mathematics from San
Jose State University in 1967. After
two years as a programmer/
Jjjfr , analyst, he enrolled at Iowa State
IfffL University and received his MS
* *V ' degree in mathematics in 1971.
. w He remained at Iowa State for the
Mm
* next two years, doing course work
W '**. m K an d teaching mathematics, then
'if / joined HP in 1973. He's worked in
*.,jife / product support as well as the
lab, and is currently doing computer performance modeling and
analysis. In 1975 he conceived and wrote the script for an HP
videotape that was judged best instructional videotape in the
nation by the Industrial Television Association. Roy is married,
has three children, and lives in San Jose. He coaches a youth
soccer team and participates in a number of sports.
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OCTOBER 1977 Volume 29 • Number 2
Technical information from the Laboratories of
Hewlett-Packard Company
Hewlett-Packard Central Mailing Department
Van Heuven Goedhartlaan 121
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•
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